All of the OpenTX/EdgeTX radios work on Linux as a controller, and generally most radios that support this probably will, because they just appear as a joystick (HID profile). There are also ways of connecting them other than just plugging the radio into usb and selecting “controller mode”, but even those usually result in a joystick device I think? So which radio in particular mostly depends on what kind of drone you want to fly, if you want to fly other things (plane, helicopter, scale models), or drive other things (cars/boats/crawling/scale models). Also ergonomics (size of hands, similar to a classic radio or similar to a game controller?) and just personal preference, mostly.

As for the Sim, I think Liftoff has a native Linux port, but these days most of the sims should just work anyway with the recent developments of valve for the steamdeck.