It seems that you are hitting a really old bug with the version of snapd that is in Debian/Raspbian here, you need to first install the core snap, then install this snap (or any snap using base: core18 or base: core20)
It seems that you are hitting a really old bug with the version of snapd that is in Debian/Raspbian here, you need to first install the core snap, then install this snap (or any snap using base: core18 or base: core20)