What options do I have to avoid API gap limit? I am using xpub keys I am building a app, and the design is, the "welcome page" has a qr code allowing the user to purchase a single-use of the app.

Blockchain.info conveniently allows you to use xpub to generate addresses, however, their docs mention bip 44, and the "gap limit"...  This is instantly a problem as I can imagine, say 30 users simultaneously going to the app (more realistically, 30 users going to the app under the amount of time it takes a single user to purchase), 20 will be presented bitcoin addresses to purchase, 10 will not due to the api throwing gap limit errors.

What options do I have to get around this?

I've had others suggest I just manually generate a bunch of private keys and not use xpub, but manually having to consolidate all of those single-transactions-per-address just sounds like an absolute nightmare that I would like to avoid.

UPATE

Is there any way at all to re-use the same address every time, but attach a guid to it so that when I see the txn broadcasted, I can link it with a given user's session?  This is really all that I need.  I don't need xpub.. I just need a way to identify that user A and user B both are viewing the welcome page, user A doesn't pay, user B does, user B is automatically given access, user A is not.
Issues related to gap limit as summarized in this blog post. Basically you have few options


Use wallets like electrum to increase gap limit setting
Automatically send small amount of funds to 20th unsued address to keep things going. This is done by services like blockonomics
Keep generating new address without worrying about gap limit. Later you can generate all private keys using xprv and sweep in the funds from all private keys.