xapo bank makes that pretty smooth, holding in bitcoin and only selling for fiat when you pay in fiat, and if the merchant accepts LN you can do that as well, and of course SWIFT/SEPA and on-chain bitcoin
they are the first neobank to go full bitcoin and i'm so glad to finally have this option... i first had a "crypto" card back in 2016 and their service was awful (wirex) and i got robbed by them again, with the cooperation of a bulgarian bank who i had an account with back in 2013, refusing to verify my identity to the bank and the bank refusing to give me back the card their "eject money first" ATM swallowed while i was busy paying immigration fees