Every vendor that is not Apple already supports Android. Even the ones that don’t want to have the GSuit built in, and some of them care about privacy, while some don’t. A smartphone is comprised of more than one cpu, and there are proprietary chipsets with closed firmware all the way to battery. This is a much different world than x86 PC with pre EFI BIOS, when you could flash everything (except cpu?)
What do you expect to be able to achieve with just the word “Linux” added to the mix? Can you build new 5G drivers for Linux as well? Smartphone market is moving pretty fast, the hardware is nearly disposable, and the consumer doesn’t even know what an OS is.
GNU/Linux smartphone, that is competitive? Good luck with that.
