Former Unity employee here.
Unity tried a similar “migration” once already , when they tried to shutdown Unity Answers. Unity devs screamed, “NO. GOD. NO. PLEASE NO.” And that time, they halted things.
But 2 years later, with Unity stock at sub $16 and the Runtime Fee-asco in the rearview mirror, what’s the worst that could happen? (There’s still time. Don’t do this.)