Ok, that's a lot of questions, I'll try to answer most of them.
The aspirations in both packs are nice. They're still Sims 4 aspirations, but they're enjoyable, and it's good to have more variety for kids. I have only tried one of the Home Chef Hustle ones, but it didn't feel too much like a tutorial, as it did have some objectives which, while easy, required some set up.
Burnout, in my opinion, is much less annoying than the fears, and in fact, I think it has added to my gameplay (a little) by reminding me to vary a sims' activities when I start getting a little one-track. You get a warning with a little moodlet, which can be cleared by doing something else for a few hours, and if you do get into burnout (there are two stages of this, if I'm not mistaken), taking a day off or two to focus on other things clears it. Burnout really doesn't happen randomly and it's easy enough to manage not to get to the full thing that really hinders skill building and career leveling. Having sims do relaxing activities or sports clears up the moodlets, as does doing activities opposite what brought on the burnout (creatives skills or "mental" activities).
Midlife crisis is pretty easy to ignore if you don't like it. Only some sims will get it. It gives your sim a +1 tense moodlet and a small buff to facilitate doing new things, and can give some extra, bigger moodlets at times (but positive and negative). You get some extra goals that reward satisfaction points and fulfilling enough to resolve the crisis (which also resolves on its own after a few days) gives the sim a happy moodlet.
I haven't really had any annoyances with Growing Together so far. I think the milestones are fine, but I rarely check them and barely ever rotate to other families at the moment, so I wouldn't have noticed.
Family dynamics and compatibility seem to affect the game quite a bit. Dynamics change the sims autonomous behaviors and compatibility can make it easier or harder to make friends, though it's nothing unbearable. You can also just refuse any family dynamic the game suggests that you don't like, so it never gets in the way of my stories.
As for B/B in Growing Together, it's simple enough to go well with most things. I'm not 100% sure about color matching and such because I use a lot of packs together. Some furniture goes particularly well with the mid-century stuff from Get Famous, and there's some craftsman stuff that pairs well with Seasons. And of course, Parenthood, considering the amount of children's stuff in the pack.
As for Home Chef hustle, the appliances are nice. They're quick and easy to use, allowing sims to do short tasks while they work (haven't tried the pizza oven yet, though). The build buy stuff, other than the counters and cabinets, is mostly kitchen clutter and appliances, so it goes well with just about anything. The pack has a pretty modern feel, and I use the wallpapers a lot.
I hope this helps!