It seems to recognize the flatpak and gave me ~5 configurations on my steam deck, but nothing on my desktop (flatpak or native)
And yea, as much as I truly love the steam controller (both of them!) and just how insanely good steam has made controller configurability compared to what came before it....... it's more than a little janky and weird at times. And features keep changing.
fwiw mine are in `~/.local/share/Steam/userdata/[ID]/ugc/[some id]/[some id]_controller_config.vdf` and the files have the display name in the content.
but I can hunt around and see if a cross-account copy/paste even works, not sure tbh.