Expansion Pack Suggestion?

This thread contains a description of many of the features, activities and items included in the packs. It may help you to decide on what pack you would like to get next, that suits how you play the game. 
https://simscommunity.info/2024/02/26/sims-4-pack-guide/

I would suggest Cottage Living. It's a great pack - beautiful world, lots of build objects that many people use constantly in their builds. Lots of new gameplay, animals - if you like that. Of course there is also Growing Together and Parenthood if you are specific about family game play. Out of the two I would choose Growing Together as it heavily improves the infant life stage, if that's something you are into. Parenthood is more about the adults.

You have the four packs that are my favorites. It sounds like you like family game play so Parenthood and Growing Together add a lot game play for that. If you want something outside of that I enjoy Island Living as a contrast- offers a tropical world that makes banger vacations and a real contrast in lifestyle- and gorgeous, gorgeous world!

My suggestions are:

Get famous: Still the EP with the most and most interesting gameplay

Snowy Escape: Most captivating atmosphere for maximum immersion

Definitely Growing Together, for family play. Parenthood is a great addition too.  

• For family play I would recommend Parenthood and Growing together. Adds parent-child interactions, character values, family dynamics and parenting skills.
• If you are playing with generations, you might consider Life and Death with funerals, wills, heirlooms (unfortunately not photos, but those can be put in the memory boxes from Growing together which can be made into heirlooms). ä

Other useful packs might be the toddler-pack, the kids-pack and laundry day. They all add items that add to the normal day to day life. If a large chunk of your player style is about finding new partners for your family members as they age up.