A far as I know paid plugin will be developed as well as free tier version.
Rendering on 1 GPU vs 4 or 8 for example for most users is a huge time saver. If you don't care how long it renders you can stay with one GPU otherwise going multi GPU is obvious.
Regarding your license I would ask support to transfer it to another 3d package.
https://help.otoy.com/hc/en-us/requests/new