I have been playing quite a lot since the problems to see how things work.
What I have learned is that the biggest problem is the size or ability of my computer. It is just not fast enough, strong enough for all that I am asking it to do.
It can handle the base game, the expansion packs of RV, Pets, WA, SN and Seasons.
AS long I don't overload it with large files it does fine. When I get families that are five generations, have lots of stuff (artifacts and such), too elaborate a home, too many remodelings on other houses in the town and more, it is bogging my computer down, it just can't run all that memory or whatever it is for that game. Thus the freezing and other problems. My games where I have lots of kids, multiple decendents and three generations in the house with all of what has accumulted, artifacts, gems, and other stuff from the families over time, it just can't handle it.
The games that have grown to two at most three generations and the families had only one child in each, moved out the oldest (founders) when the third generation was born, very little remodeling of the houses in town or adding a lot of extra rabbitholes above what is in the game, they are doing fine.
I'm going to uninstall sims and then reinstall all the expansion packs except Pets, I didn't like it that much. Keep my games short, no big families of five kids, having the limit of 8 sims in the houses, big, big houses which are full from collecting stuff.
I hate losing my families
but if I want to play it without having all the problems, then I have to start fresh and watch how much I do. Until I can get a stronger, faster computer that can handle all that I want to do, I have to stay small.
Keeping caches clean, doing all that has been suggested here has helped a LOT, but several families are at fourth or fifth generations, with five or more sims in a home, with a lot of memories from the family members that has built up over time. I just can't play them anymore, that file, game is too big.
I hope this helps anyone who has been struggling with what I have, the freezing of my sims, everything is going on around them, branches moving and such, but sims aren't. In smaller games no problem, bigger games, it keeps getting worse. Sims not responding, too much for my computer, it just couldn't handle it, sims takes up a lot of energy on my computer when it is running.