Yes, like many you probably have the habit of not closing documents that you work in. My experience is that closing the open pages, microflows, domain models, mappings, etc. will make Studio Pro perform well again.
More people have the same experience, by the way. See https://forum.mendix.com/link/questions/98176. That answer also suggests other tweaks that help a little, like switching off the AI-assistant, but they only help a little bit.
Also: I regularly have several projects open in several Studio Pro’s at the same time and they all perform quite ok. Just to say that they do not harm each other.
I hope it helps!
I experience the same but it seems (to me) independent from AI assistant.
It’s building up a cache file that grows and grows.
I have to commit changes (which can take a long time), close everythink and reload. That’s setting performance back to normal for another 4-5 hours.