Currently mpd can't be started since it is looking for libnfs.so.12, however libnfs version 4.0.0-3 provides libnfs.so.13. Downgrading libnfs to version 3.0.0-2 fixes the problem as that package provides libnfs.so.12.
On a side note: I think a proper bug tracker would be better than using the forums for that. Your gitea instance would probably be better for that, but I can't find a way to register there.
If you don't want to downgrade, a temporary solution would be to make a symlink for the required file, pointing to the existing file.
This kind of problem is expected, and will continue to happen as long as we use mixed repos (Arch+Artix). We will eventually package all of the software, and then this will not happen.
Problem fixed with latest mpd package