Meta Data for Client Relayed MP

I am writing a TBS using client relayed MP through nakama.
I want to implement match listing for the client, so a player can browse and join open matches.
However client-relayed matches do not give me anything to store meta data, such as a map name etc. All I have is the match ID and the Size.
Is there any way to have some meta data attached to the match?
For example I don’t see any reason why a label would not also work for non-authoritative matches. I really only need a single string and I don’t really want to rewrite everything to make it server-authoritative just so I can retrieve a single string from a match.