record gameplay?

Medal is a desktop app that allows you record your game sessions. It really wants you to participate in its own environment, which is kinda like... I dunno, tik tok for game clips? I don't. I just use it for recording gameplay that I then upload to YT. It records in decent quality, with decent audio, it can record game audio only or all audio (game + mic input), it can record Discord audio (if you're doing multiplayer and you're in a Discord voice call with your team and want to include that audio in the video). It's free to use with ads. I don't find ads to be very obtrusive, it's a banner add here and there, but so far I've seen no full-screen popups. It technically has some basic video editing, but the capabilities (at least in the free version) are limited and the UI is meh. 

tl;dr on Medal: it hasn't done anything to annoy me enough to stop using it yet

Screen recorder: mind you, I've only ever used Samsung tablets, but I would assume that at least other Android devices have that built in as well. Pull down the widget menu from the top of the screen, open it up to the expanded view, and one of the options there should be called "screen recorder".