Continuing the discussion from FP6 Restart the phone to load the corresponding configuration - 15.148.0 - US/Canada:
Ok so in my eyes the network issue is a different one and should better not be mixed here in the other topic, so with my response for further troubleshooting I opened a new topic for you for this.
When things like 5G, VoLTE etc work is dependent on the provider (as well) so if not done yet get in contact with them, test another providers SIM and test with 4G/3G/2G. As for whatever reason 5G foes not work and the setting still active this might cause issues.