That's because this OGL nonsense is a super shitty money grab by Hasbro.

Sort of. They're unsubbing from D&DBeyond and not buying any more products from Hasbro, but playing D&D with materials you already own won't give them a cent so it doesn't matter. Especially if, like what OP is looking to do, the group is playing live instead of on a VTT because then there's no metrics to track in case Hasbro looks at outside VTT metrics to see how the game is doing. Not that I think the company would do that, I don't think any of the decision makers there actually understand the industry enough to think to do that.