I followed the instructions here for the manual install and went ahead and run it for the following paths:
$HOME/.var/app/com.microsoft.Edge/config/microsoft-edge/NativeMessagingHosts
$HOME/.var/app/com.microsoft.Edge/config/google-chrome/NativeMessagingHosts
$HOME/.config/chromium/NativeMessagingHosts
$HOME/.config/google-chrome/NativeMessagingHosts
$HOME/.config/microsoft-edge/NativeMessagingHosts
with the last one not even existing but it would be the one if edge was running natively.
Then also went ahead and run
flatpak override --user --talk-name=org.freedesktop.Flatpak com.microsoft.Edge
which should disable any sandboxing for edge. Rebooted. Nothing did the trick. RPA still shows all 3 xmodules as not installed.