It’s ambiguous today how to handle more values in tags - except for a few NIPs that define second, third and forth value - like pubkey, relay pet name (NIP 03) or hex, relay, marker (NIP-27).

Data architecture wise it should likely be split into a tags and tag values m2m table.

However does [p, PUBKEYA, PUBKEYB] become two instances of tag values both pointing to tag p - or does PUBKEYA have a relationship to PUBKEYB, and it wasn’t a normal p tag.

SQL wise, it’s hard to model correctly.