It seems that you are in the same situation as I was. I had a couple of posts regarding the matter …
Grace Period Update to Cubase 12 - Cubase - Steinberg Forums
Grace Period Update to Cubase 12 - Cubase - Steinberg Forums
I don’t know what the current situation is regarding multiple licenses for the same product. I ended up contacting support to help me make my second Cubase Pro license eligible for the Nuendo crossgrade. Didn’t need two Cubase Pro licenses, and also have another Elements license which I may never use at this point …
Anyway, I think they might have overlooked a few things/somewhat unique situations when designing the new licensing system. Although I would think it to be pretty common to have more than one license of the same product. The crazy thing is … nobody even knows how to transfer or sell a license if no longer needed with the new licensing.