The only way to get remote play working on Linux is to use Steam Link. The safe(r) option for this proprietary blob is to use Flatpak and the package at:
https://flathub.org/apps/details/com.valvesoftware.SteamLink
The Steam Link app works fine if I do:
flatpak run com.valvesoftware.SteamLink
or if I open it through the GUI.
But when I attempt to debug the app(because of a network-related issue) by running:
flatpak run --command=sh --devel com.valvesoftware.SteamLink
It gives the following error:
error: runtime/org.freedesktop.Sdk/x86_64/20.08 not installed
Any suggestions for getting into debug mode?