Make your own engine, open source it, get plenty of traction, then make money off it as its premier consultant, or have a team who specialises in porting, etc.

Make your own engine, open source it, get plenty of traction, then make money off it as its premier consultant, or have a team who specialises in porting, etc. The first bit will take time. Or you might have a "hook" which speeds up the traction part a bit (like Bevy being made with Rust, I guess).