My point is, there is a standard for QR payments (I think it's ISO 5201 but it was a long time since I dealt with that). Cross-border support will depend on the country/bank support; but theoretically if everyone adopt it, you'll be able to scan any country QR and then use your wallet to transfer funds (assuming your bank support cross-border payments).

I think ASEAN largely adhere to the standard though the cross-border part is limited to ASEAN.