I've got a few from PowKiddy. They're all based on the Rockchip RK3566 SoC.

There are some other chips coming out that have decent Linux support too, but the majority of devices will have that one still.

What system do you want to emulate up to?

If most PS2 games and Gamecube games are good enough, you can grab an Odroid Go Ultra cheaply. It's what I used and suited my needs.

Keep SteamOS on your SteamDeck and come join the SBC debate and in https://old.reddit.com/r/SBCGaming/

First you need to define “everything”. It’s easy to get a device that runs every 2D retro game ever. But, moving up the 3D emulation ladder can move right past the SteamDeck into more power hungry devices.

Most RK3566-devices are a good bet. I have the Powkiddy RGB10 MAX 3 which runs Rocknix great.

I have an anbernic rg35xx h - it's a great device; totally recommend it. It plays games up to ps1 with easy, it also works good in most psp games, maybe with a little frameskip on more resource intensive games.

Very good controllers and firm design. Great value for its price!

I’m running bazzite on amd kit and it’s blown me away how nice it is, everything so far has ”just worked”

It's a form of JELOS picked up by contributers in the wake of the project getting dropped after Nintendo went after Citra. JELOS shipped with it by default.

Source: I've contributed to Rocknix and was around for the dissolution of JELOS and the fork.

I think it's because the SoC hardware is made by Rockchip.

I don't believe there's Bazzite or SteamOS available for ARM devices, which make up most of the "portable handheld" market in terms of device variety