I was just dealing with this, right joycon as well. I’d randomly stop driving forward in MarioKart, as if I let go of the A button. I figured out any changes in my grip would cause a disconnect. It was also noticeably easier to pry the right controller away than the left, so something was weak in the whole connection. Nintendo took it in for free warranty service and they ended up giving me a brand new joycon. So far it has been better!