As far as I’m aware, that shouldn’t be an issue. I know for sure people are allowed to have multiple Itch.io accounts, assuming they are not using them to upvote their own content (which is against the rules).
Users are allowed to have one account for game dev, and one to play games, or one for NSFW games and one for family games.I don’t see why paying on the same bank account would cause any issue on this.
Having said that, I’ll confirm with an admin if that’s the case, and will post an update here if this is not allowed.