I think this would be an ideal use case of Cashu (Cc nostr:nprofile1qqs9pk20ctv9srrg9vr354p03v0rrgsqkpggh2u45va77zz4mu5p6ccpz4mhxue69uhhyetvv9ujuerpd46hxtnfduhsz9thwden5te0dehhxarj9ehhsarj9ejx2a30qyg8wumn8ghj7mn0wd68ytnddakj7xph5zr). The only problem is that mints can't do keysend now. There should be a way to get the node to give us invoice that would be processed and logged on the server side as keysend. At least until v4v spec adds either lightning address, or even better bolt-12. But there should still be a way to do keysend payment, as podcasts won't have to migrate. 

Cashu would add a choice of custodians, self sovereignty, privacy but no need for channel management. 

Another option is Nostr wallet connect, but that would not expand the selection that much, it's pretty much Alby and mutiny these days, while mutiny is shutting down. But hopefully NWC will be adopted by more wallets. 

Both Cashu and NWC are usable from web, with very simple APIs, so implementing this is possible even in the browser apps (PWAs)