Hi!
I don't know if this is news to you, but the golang toolchain for ARM64 works out of the box.
In the terminal:
$ wget -O go1.21.1.linux-arm64.tar.gz https://go.dev/dl/go1.21.1.linux-arm64.tar.gz
$ tar -xvf go1.21.1.linux-arm64.tar.gz
$ ./go/bin/go
Go modules seem to work as well. Hopefully this will turn out to be a good toolchain to work both externally and within the phone.