You could start start watching the #math hashtag, or search for it e.g. on nostr.band , you’ll find people with math in their bio, notes, etc
brugeman (npub1xdt…ntxy) paid service idea? Ability to search nostr by “hashtag cloud” (words related to one one topic) in one search?
For #math that could include e.g. the tags from https://math.stackexchange.com/tags