My Claude subscription is through iOS IAPs.

I could swear I didn't even see the option for an IAP on iOS… maybe it's region-locked?

Maybe, but I wouldn't suggest doing it even if you figure it out. It has some really annoying side effects on subscription management for Claude, and additionally they mark up the plan cost by 20%. Which I didn't care about on the $20 Pro, but now with $200 plans.

I haven't figured out* how to switch to a direct subscription other than cancelling and resubscribing, and I'm afraid of messing up my account access.

* Caveat that I haven't spent more than 20 minutes trying to solve this.