Oh add force is actually a little tough.
The first thing coming to mind would be setting a max velocity, dividing that by the current velocity to have a number between 0 and 1 swap it (because right now 0 means 0 velocity. So we subtract 1 and get the absolute).
Then multiply your force with that number so you apply less force the closer you are to your max velocity.
It’s less then ideal though and it feels like there should be a better solution… But I’m not sitting in front of an engine right now to test.
Sorry for that.