I’ve never connected a MacBook to an external monitor before. I’m just a little worried the computer would get too hot while I game and will damage it somehow. It would be for occasional league of legends gameplay. Nothing intensive.
Apple designed it so you can connect to External monitor so it is safe since it’s 100% supported. Don’t worry about the heat, I run my 2016 MBP 15” in clamshell connected to an external monitor and do a combination of gaming and programming and some photoshop. Never had any issues.