Script to easily install / uninstall Android via Waydroid on the Steam Deck running on SteamOS. - ryanrudolfoba/SteamOS-Waydroid-Installer
Android games are normally going to be inferior to Steam games, but this is still a nice option for games that aren't available on Steam or can't be played due to anti-cheat reasons.
You can read more about Waydroid here.
There are reasons to believe valve is working on adding official Waydroid support to Deck, but until then you can install it this way.
Bazzite has it by default, for anyone who wasn't aware. As for official Valve support, I feel like that's just wishful thinking; I'm not going to get my hopes up until we see more official news about it.