Blender Animation running very slow in viewport, but only occasionally

this is my first post!
This seems like a question that has been asked many times but I can’t find an answer to my exact problem.

For me, sometimes, the animation in the viewport has extremely low fps, like 2-7. Even when there are no keyframes set! I have been experiencing this with the Rain Rig, simpler scenes or rigs usually work fine when the issue occurs, but do have some fps drops that normally are not there. I need to fix this problem because I use the Rain Rig for university work and sometimes waste a lot of time.

By "sometimes" I mean, that it does not happen all the time. When restarting my laptop and generally trying around, I somehow manage to fix it, but I never know how I fixed it. Last time it took me about an hour. But when I do fix it, everything is working really smooth and fast, even with a ton of keyframes.

I think it might be some problem with my laptop? But I really don’t know what it could be and I’m starting to go crazy, so I hope someone can help me out. Is there anyone that knows what could cause this problem?

It was requested to show that I use GPU for rendering: