I skimmed some of the comments from that giant Reddit thread. A lot of people responded that they’ve been buying even more Apple gift cards without problem.

One commonality among the stories in that thread from people who had problems was either switching their App Store country or using their App Store account primarily from a different country than the setting.

Well-spotted.

That includes the original poster! "could have been because I purchased gift cards from the US (online) and added them to my account while I was in Mexico, or I was using a VPN while adding gift cards"

One of the other people was someone who "purchased $2k in apple gift cards from target during Black Friday deals... There was a limit of 1 but if you went in store and were friendly to the cashier a lot of people (myself included) had luck getting them to ring them up as separate transactions".

Pretty sure if the latter person had given those out as separate cards to other people it would have been fine but going from "limit of 1" to "all redeemed by same account" is unsurprising when it triggers a fraud flag.

The big problem in this story as in the past one is the apparent lack of sensible escalation.

I've heard horror stories from Google devs that it's even worse - such a situation follows you for life even if you try to setup new accounts.