would a service like privacy[dot]com which generates custom one-off credit card numbers with custom spend limits be useful? (Not affiliated, I just use them from time-to-time exactly for that purpose)
Privacy.com is awful. You forgo the credit card protections, they need full access to a checking account, you can't do chargebacks, you lose any cashback methods.
Use a virtual card from your credit card
Many banks offer these now a these days (Capital one does, with all cards, in app or in browser, no need for extension).
