With the major controversy of Unity throwing game devs under the bus, a lot of people have been looking into moving to Godot. I'm writing this post from the ...
I made a blog post about my experience switching from Unity to Godot earlier this year, and some tips for Unity devs.
As far as I know Unreal’s source code is available but the licensing isn’t, so the company still owns it and can still charge you for using it.