I don’t have the stuttering you’re experiencing so I’m just guessing. When I think of your problem I think about what could be different between flying in the air and flying near the airports. 2 things come to mind. You might give these a try.
- there’s settings for AI traffic, cars and other “airport life” type of things.Maybe turn them down or off.
- there’s always contant ATC communications around airports. Maybe try those settings.
Good luck.