Is this a browser thing or Windows thing? Or Sketchup thing?
Can’t be sure. If you are using SketchUp 2018 still, you could go to this folder:
and delete the WebCache folder, then reopen SketchUp.
Is there a reason you’re using SketchUp 2018? I think that you have a 2019 license you haven’t yet used. You could download 2019 from here, and see if it works better: