Pretty sure Obsidian uses a plug in to make it work with nostr and I don't think it been out all that long. To be honest I haven't tried it out yet so can't help you...perhaps its worth using a specialist nostr client for now?   @NunyaBidness have you you tried anything nostr related on Obsidian? 

 I was in touch with a developer for the plug in yesterday and found it was an issue with the plug in itself and is currently being looked into. 
Might have to go the specialized client route for the moment though.