I am at Home with a Galaxy S22 Ultra right next to WiFi. If I turn it off, I have 5 bars of 5GUC on T-Mobile. Either way, ARC says Poor connection and will not play music. My Enby server (on same Linux box) works just fine on my phone.
Poor connection messages even on home wifi can usually be fixed by resetting the ARC app from Home > Settings. Sometimes, an uninstall/reinstall is necessary.
However, you will lose any downloads in ARC in either case.
I run into this bug with my iPhone from time to time (doesn’t happen on iPad for some odd reason) … happened again so I’ll have to uninstall/re-install the app (and lose all my downloads yet again) Another reason I still use and rely on Plexamp.