>> Probably in the long run the only way to go will be to own/carry two devices.

Been doing this for a while. I have a smaller Samsung S22 for the apps I absolutely need that won't run on my Graphene phone. The majority of my day-to-day stuff is handled on my older phone running Graphene.

Been tinkering with Ubuntu Touch, but AFAIK they haven't figured out how to solve the issues with VoLTE yet here in the US but its on my radar to try and make the switch soon.