I don't understand how you feel you're losing out.
You're getting refunded for something you already paid for, and you're going to get a free upgrade to the next version - which you presumably would have had to pay for,...... but not really since as an ArchiCAD v23 user (which I presume you'll be), you would have been getting it free anyway regardless.
What am I missing here?
Non-ArchiCAD users of Twinmotion (and presumably ArchiCAD users who won't upgrade to v23) will have to pay for the next version....which you will get for free.
I would imagine that it's THEY who would feel like they're losing out on something (but again,.....not really. No one promised anyone any free version software and even as an ArchiCAD 23 user, this is just a one-time promotion for both software that both companies are mutually benefiting from)