Very interesting! I'm going to have to test if I can switch my Asahi ALARM M1 Macbook to official repos. I know when I use the AUR for packages, they typically have both x86 and aarch64 paclage instructions, maybe 10% or so don't and then I just clone the file and add it in manually.
You can start by changing only the extra package url to the aarch64 arch linux. Do keep in mind that while the aarch64 pkgbuilds are official arch, the package building and distribution is community. they're currently compiling for armv8.2, while some are maintaining armv8, and these mismatch can cause program to crash with illegal instructions and what not.