Zenless Zone Zero — Is there a limit on how many codes per account?

Bit of a niche question, but this seems like the right crowd for it. The in-game explanation and the actual behaviour do not appear to match.

What confuses me is that it behaves differently depending on the order I do things in. Corrections welcome, especially if I got a detail wrong.

Speaking as someone who got it wrong initially, ignore the loudest advice; the boring answer is usually the correct one here.

Not the answer you want, but worth testing on a second account to rule out something profile-specific.

This comes up a lot, so: region and server load matter more than most guides acknowledge.

Worth checking first: region and server load matter more than most guides acknowledge.

Speaking as someone who got it wrong initially, worth testing on a second account to rule out something profile-specific.