@jarkko yw!
FWIW, keep in mind that this is not a vanilla kernel you are building[1]; there are not many patches kernel-ark applies, but quite a few nevertheless: https://src.fedoraproject.org/rpms/kernel/blob/rawhide/f/Patchlist.changelog
You also might insert a "git checkout ark-latest" between step one and two, as sometimes that branch will contain changes needed to make the kernel compile.
[1] to everyone interested in that: if that's your goal, using arkify might be better fit: https://gitlab.com/knurd42/linux/-/tree/arkify-arkify
@jarkko and reg. the "It probably would make sense to put a remark here"
Yeah, that likely is wise. I forgot about that "make dist-test-patch" thing myself. Maybe I or somebody else that sees this thread will submit improvements to the kernel-ark documentation to mention that.