I have good news! Until today, my file had been completely hosed. It was 220,000K in size and nothing but random build/buy changes were saving. I fiddled with the file, tried using different versions of it, repaired my game twice (even did the thing where you remove the whole Sims folder and force the game to recreate it), and nothing helped, so I finally gave up last week and resigned myself to placing the Sims I'd saved in my gallery to a new file and starting over.
Well, after today's update, I noticed that the new file I'd been playing for about a week now had strangely DECREASED in size when I saved it just now. And that was after I'd added a couple new lots to the maps. Hmmmm.
On a whim, I loaded the "corrupted" file, let things run for a while (gave the Sims time to get to sleep), then saved again and the file size reduced from 220,000k down to 8000K AND when I loaded the game again, everything had saved! The Sims were in bed where I left them!
I have no idea what happened or why, or if this file is "all better now", but maybe I can play it long enough to finish the stories I was working on with it and then just move on to something else. But it seems like something in today's update fixed "something" because that is a huge change in file size when I did nothing but let the game run for a few minutes. I didn't delete anything from it.
So, hopefully today's update with help a few others that have been having this problem with saving progress. 🤞