The concept of open-pleb by nostr:nprofile1qys8wumn8ghj7mn0wd68ytn9d9h82mny0fmkzmn6d9njuumsv93k2tcpz4mhxue69uhhyetvv9ujuerpd46hxtnfduhsqgxyk5mf48dj0ghphjtmyha2fp3dnl86w36sdv0jwtu0fvmtsykm6c90er2r is amazing (still WIP). It's a marketplace to match (1) a seller who has bitcoin but would like to pay a fiat QR code and (2) a buyer who has fiat and would like to stack non-KYC Bitcoin.

(1) seller walks into a store, chooses goods and has the option to pay via QR code (could be alipay or a million other payment systems globally). They put up an equivalent amount of ecash with a coordinator who then starts looking for someone on the other side.

(2) gets a notification and opens app to see there's a QR code waiting to paid. They pay the QR code and provide a proof to the coordinator.

If both users agree that the payment has taken place, the coordinator sends (1) the sats that (2) has put up.

If this works this is IMO the best way for stacking Bitcoin. No exchanges, just two regular people with two separate wants that meet each other on the internet.