rouge harbour lagging from mtx

I love the game, i love heist but it is making it impossible for me. Fps outside the grand heist planing room goes from 4 fps to what i have max. Inside the room is fine.
when some mtx starts doing the animation, it lags and sometimes just breaks everything. My pc is old but it is over the minimum. I don't know what to do.

Any solution other than better pc or don't play? Thank you.