Ok thank you, I’m guessing the pi zero w is too old to run snapd and only just found a seemingly related previous post here Installing snap on Raspberry Pi fails
Presumably I should be ok with the latest Pi 4 or Pi 400 models? - my goal is to install the gutenprint-printer-app https://snapcraft.io/install/gutenprint-printer-app/raspbian#: and to use the pi as a wireless print server.