I was just evaluating it yesterday, but honestly a service that uses Nostr but does not have an account on Nostr and asks for one's nsec to log in without using NIP-07 or NIP-46, for me is to be avoided like the plague.
https://paywithflash.com/ can’t remember who noted this on nostr but I saved the link. Maybe it’s something you can use
I was just evaluating it yesterday, but honestly a service that uses Nostr but does not have an account on Nostr and asks for one's nsec to log in without using NIP-07 or NIP-46, for me is to be avoided like the plague.