What about per-topic #nostr #relays that only #relay notes including a hashtag from a declared subset of related hashtags. So you can enable all the relays for topics you’re interested in, and know that your notes will go to the right relays based on the hashtags you use.

Eg. A Bitcoin relay declares that it filters on hashtags X Y and Z for notes it receives for clients

Seems easier than making clients or users have to manage which relays they send which notes to

#nostrasia