Hey Akira_San!
You are right, those engines are now “gratis”.
1) That does not change their maleficent proprietary nature that forbids you to use your four freedoms
2) I’m doing this project for fun and I have no fun when using one of this ready-made solutions. I want to tinker 😀
I will not stop working on Neo just because someone else decided to make their product “gratis”.
Neo is not competing with Unity and Unreal anyway due to a lack of man-hour and money.
Have a nice day!