How is it possible to generate more than 10 2FA Backup Codes?

How is it possible to generate more than 10 2FA Backup Codes?

This would come in handy for users that have no smart phone or DAU users. I could just give them a list of backup codes so they can use 2FA. But only 10 codes calls for an administration nightmare… I was more thinking like 40 because Zimbra permits max. 40.