Big Sur is installed on my MacBook Pro 2015 lately, so far everything is stable for me.
What is not stable is the Sims 3 Metal. After the update won’t the game start.
Clearing of Mac Cache and cookies didn’t help. I hope that Maxis can fix this soon as able and the game runs more stable on 64bit.
I gonna use it my dynamic containers (AFPS containers & partitions) where I installed Mojova. There I will reinstall the old version of The Sims 3 there. Everything else is a catastrophe