Resetting in-app purchase promo code limit App Store allows only 100 promo codes for the app and for each in-app purchase. App's promo codes are reset with every version update but it turns out that IAP promo codes are not – after spending 100 of them, there's still 0 available after updating the app's version.

Is there any way to reset them other than creating a new IAP (which would be troublesome for a non-consumable because of the purchase restore).
You can't manually reset the in-app purchase promo code limit. These reset twice a year.

You can provide up to 100 promo codes for each in-app purchase item, with a limit of 1,000 total in-app purchase codes per app every six months (resetting on January 1 and July 1).

Manage promo codes - App Store Connect Help