something definitely changed. I already posted about this here https://discussions.apple.com/thread/253040104 but I'll repost here too:
I have a 16gb M1. got it in november 2020, was very happy with it. I was able to open ALL the apps I routinely use, and just leave them all open! numbers, safari with several windows and dozens of tabs (including 4 large and complex google sheets, big enough that every time I went back to them, safari said they were reloaded for using too many resources lol), DEVONthink, fantastical, omnifocus, iTerm2, 1password, plus a whole slew of iPad apps. so many apps, in fact, that my dock became a tiny little colorful ribbon and the CMD-tab switcher was useless. it was glorious.
then right after a software update (I believe it was the 11.3 or 11.4 update, not exactly sure), I can't do that any more.
now most of the time when I wake it up from sleep, I get the dreaded "your system has run out of application memory". so now I'm in the habit of running an app when I need it, then quitting it. normally when my mac goes to sleep, I only have omnifocus, iTerm2, Finder, Messages, 1password, and obsidian running. and sometimes upon wake, MacOS will kill iTerm2!
I have activity monitor running now, showing memory usage for all processes. the memory pressure at the bottom is always green.
meanwhile, my work intel macbook pro (also 16gb) still routinely has 25 apps open without trouble, but my m1 with only 6 or 7 is complaining.
I do have some background things running, like backblaze, Hook, Hazel, some setapp apps like Paste, Forecast Bar, iStat Menus, Timing, bartender. but all these were also running before the software update, when I was running tons of apps all the time without trouble.
I'd bet dollars to donuts this is a MacOS bug, and I guess I'm just cathartically posting here that I wish they'd fix it.z
I suppose I should make another account just for the fun of it and see if I can run lots of apps there, but since I don't see any culprits in activity monitor, I'm not sure that will help.
P.S., I'm not running VMWare or adobe or anything like that