The site has performed more or less the same after the staff cuts as it did before. I say this as somebody who has used it nearly daily for ten-ish years now. Most users I know have the same experience. Maybe you noticed something if you're parked on Twitter for hours at a time, but I try to limit my exposure to people that do that.
I get that Musk is a dipshit and that there are other problems with the site since the change of ownership, but the griping about stability seems to come from people that don't actually use it.
It's becomming slower and slower over time. Feeds often don't load properly. Refresh only works properly manually since the feed often disconnects. Dragscroll (or whoever it is called when you press a button and you can scroll by dragging the mouse up/down) is broken and results in 100% cpu load and a stalled site until you cancel it. But these are just my annoyances, maybe it's just me. I'm switching it out for alternatives as much as possible anyway.