Opinion

This is a link to a thread that contains information about each of the packs, and features, activities and items that they contain. It may help you decide what to buy. 
https://simscommunity.info/2024/02/26/sims-4-pack-guide/
I like all the packs that you listed! Seasons though is one of my favourite as it adds a lot of features to the game. The differing weather, seasons and activities that come with these are great for our sims to experience in their sims lives.

My opinion:

• Horse Ranch - fab pack if you like horses. I love the world with all the ranches and I like to see my sims riding, training and breeding the horses. Nectar making is very profitable! The mini goats and sheep are cute and I like that you can get wool and milk from them.
• Growing Together - great if, like me, you are a fan of family gameplay but probably not as much content as other packs.
• High School Years - I only bought this for the build/buy when it went down in price. Following teens to high school is boring, there isn't much to do there and all the teen 'features' are unexciting.
• Seasons - fab staple pack, though you should be aware that there is currently a game bug where it rains and snows indoors through the roof. Very annoying and it ruins screenshots unless you turn the rain and snow off, but that kind of defeats the object of the pack.
• Get To Work - the scientist career is still one of my faves after all this time. The doctor one isn't bad, the police one is a bit rubbish.
• Discover University - I do love my sims getting degrees, but it's a bit of a repetitive slog and they need to do THREE semesters at least, depending on how many classes you choose for them to do each time. I tend to do one semester and then rotate away to another household for a break and then go back and re-enrol them at a later point.

If you like holidays & seasons, get the Season Pack.  For family play, I recommend Growing Together with High School.              As for historical Western play, I recommend Horse Ranch.  And finally, for Sci-Fi fun, Get to Work with Discover University.

What pack to choose depends on what gameplay interests you

• Horse Ranch: playing with horses is fun but a very specific focus. If you like caring for animals this is definitely a good pack
• Growing together: great for family gameplay. This is one of those DLC that are more in the back ground and can be felt in small details, rather than obvious in-your-face gameplay. It makes infants more fun but also very challenging.
• High school years: Great build and buy objects but I don't like the gameplay. I hate the fact that you can't turn of body hair growth and the social bunny on a global level. It has to be done for each sims seperately
• Seasons: great basic gameplay. The holidays and weather really give a sense of time passing in your game. I consider this pack rather essential
• Get To Work: Despite being the oldest EP, it still has great things to offer. The retail option is very useful to set up stores that can sell almost anything and remain (Businesses and hobbies is more limited for sales). I also like the science career and the aliens but know some simmers don't
• Discover University: Studying is quite challenging if you take 3 or 4 courses a week. But I enjoy it. The flexibility to attend university whereever you live, in any world, allows to combine this with playing a family. The 3 new careers and the robots are nice to have as wel.

Personally I would choose Seasons or Growing together first because their gameplay can be seen in everyday life of every family you play. Horse Ranch, Get to Work and Discorver university require you to actively seek out the game play but they are fun to play if you are interested in their theme. High school years is one of the few packs I regret buying so won't be recommending that one but I know some simmers like it. 

I love Horse Ranch for the world and for the horses. I shamelessly pleaded for horses for years lol and was so happy we finally got them. It also adds some lovely rustic build/buy items and I personally find it blends well with Cottage Living and Outdoor Retreat. Get to Work has a lot of essential gameplay for me and opens up a whole new way of going to work with your Sims at the hospital or police station and my personal favourite...the science lab. For a really immersive career experience I like to mix the Robotics from Discover University with the science career by extending the work day and adding the Professional Slacker Trait so my Sims can do what they want rather than follow the daily tasks. I edited the lab to add a robotics department and fill it with DU bots, drones and Servos created by my Sims. It also adds the Alien world of Sixam to be explored. So I have an Alien department too. It also fits nicely with Strangerville for me. I would usually recommend the retail lots from GTW too but there is a current bug with making purchases, once that's fixed the retail lots are great to design and stock with creations and collectibles but that can also be done with Business and Hobbies in a small business. Seasons adds lovely content including my favourite skill which is flower arranging but can be a little frustrating for gardeners as the seasons will affect planting as all plants become seasonal. So they would be my top choices anyway.

I really love Seasons, Get To Work, and Growing Together! The other ones aren't that interesting to me, so I have not bought them.

Get to work, you get 3 new jobs (scientist, doctor and detective) and the ability to run your own shop.  Growing Together and Seasons are good, too!

These are my 3 favorites to start out playing a well rounded game. 

• Horse Ranch- I like this pack for the horses, you can even make a unicorn in CAS. I like the world, and I like the horses for my Sims. This is one of my newer packs, but I have already given my Sims some horses, and have enjoyed it so far. Horses are a fun way to get your Sims out of the house. You can make them, or adopt them. 
• Growing Together-I don't own this pack, so I can't give an opinion on it so far. It is on my list, though.
• High School Years-Bought this mostly for the outfit option in the bubble tea store. It was a good way for my Sims to do rag to riches I needed them to do. You can create an outfit, and put it on sale from the available options.  I also bought it to give my teens more options, and to meet their own age group. You can go to school with your teens, and get them through the day. One downside if you follow them to school, the NPC teens may not be the same group as the ones from the day before.
• Seasons-I like this pack, because it does have holidays, but also can effect your worlds. You get fall, winter, spring, and summer in each world, and the weather varies. To me this is a more passive pack, but you do get Father Winter, and I think some other NPCs from it. I don't ever regret buying this pack, because it makes the Sims 4 feel a bit more real.
• Get To Work-You get the Detective, Scientist, and Doctor with this pack. You do have to go to work with them, and get them through the day in order for them to get a raise in their career. You also do get aliens as well, and your Scientist can go to the alien world when they are a higher rank. So far some of my Sims are Detectives or Doctors, haven't done Scientist yet.
• Discover University-Mostly got this one, because in previous Sims games I always got the College packs for my games. It gives your Young Adult Sims some things to do, and is pretty similar to High School years, but with a different age group. It also came out before High School years. So far I haven't played too much of this pack, because getting degrees for the Sims can take a bit to get. 

I bought all the paks in order but for game play my favorites are:

Growing Together which has lot of additional game play for infants, toddlers and children, as the younger ones learn a lot of “firsts” in this pack, like infants rolling over ( the game play for infants with this pack blew my mind. ).  Toddlers have some firsts too, and children get a tree house, bikes, and loosing a tooth.  I also like the world. And it comes with a new lot type.

Horse Ranch:  we already have Cats and dogs, Cottage living and, my first pet stuff for animals, Horse Ranch adds good game play with horses, sheep and goats, and a nice little western desert town.

Get to Work.  This pack has a lot of game play with 3 new jobs/careers you can follow your sim to work with, retail and Aliens.  The world is small, but the game play is large. 

Others:

Discover University: doesn’t do well with rotations, and I think the game play is boring, but it does  add making Robots, things like the Teacher and lawyer careers (rabbit holes ), and research and debate.  Small town

High School Years.  The game play is a  bit boring to me, and you can’t pick what kids go to school with you.  You can only have the one high school and it has to be in the one lot in Copperdale, but you are allowed to change it.  It has  good Build /buy, and CAS   It has a Carnival, but I don’t really see many others showing up there and it has rabbit hole rides.  It comes with a bubble tea thrift store, that you can buy or make outfits to wear or sell that go in you inventory.  I think the premade ones to buy are terrible.  But, you can have your sims make outfits to wear or sell, based on what’s hot at the time and what’s not. But it doesn’t show the outfit once in goes in your inventory, unless you wear it. The thrift store seems a bit unfinished to me.  It’s a small town, but a cute mining town.

Seasons :  too much rain and snow. , Winter restricts fishing in frozen ponds. No additional world.  Build buy/CAS is ok.