Hi Robert, There are some options for this.  Just keep in mind that not all Android phones are supported.  The most functional ones are LineageOS and UBPorts.  KDE Plasma Mobile is also an option.  There are others out there, but I'd consider these to be the best options.  It also depends on how you want to use you GNU?Linux phone.  If you don't need to make voice calls with your phone, PostmarketOS supports a lot of phones.

Skal!