Then you can have ARM64 Linux which boots on anything what has UEFI, like today having x86/x64 Linux which boots on everything what has x86 processor inside und

Then you can have ARM64 Linux which boots on anything what has UEFI, like today having x86/x64 Linux which boots on everything what has x86 processor inside under expectation that the mother board has BIOS/EFI/UEFI as well. Just look on Android phones - i.e. Lineage OS, special Android build for every phone. That would not be necessary if booting process would the same.