Microsoft Edge has some interesting properties for this project:

- It's a fork of Chrome.

- It has a Linux build.

- It has a kiosk mode.

- It's probably not the browser that a Linux user would be using for things they care about, so it has no authenticated state.

It should be relatively simple to add Edge as a non-Steam game, with a kiosk session pointed at rcade.dev. That would allow people to add an rcade.dev tile to their SteamOS game library, and play any of the games on the platform.