F-DROID MENTIONED, I REPEAT, F-DROID MENTIONED

F-Droid is a fantastic app store. You'll find a lot of really cool software there, most of which can't be found on the regular Play Store, such as NewPipe (which allows you to do all the things a YouTube Premium subscription does for free), AuroraStore (an alternative client for the Play Store that doesn't require a Google account) and AAAAXY (a rather intriguing non-euclidean puzzle platformer). Best part is, every app on F-Droid is free and open source and none contain ads. Side note, consider supporting developers.