There's tons of emulation handhelds produced in the PRC. The android-based ones tend to have nicer ARM chips and decent screens, and Valve is working on ARM support for SteamOS. This gets you a less powerful but more efficient SteamOS handheld, which allows you to play tons of pirated games or emulated games. You can also stick with android and use native emulation software, including windows emulation for PC games.
Steam Deck is too expensive now, IMO, to recommend over these devices.