There are lots of things you've learnt for Windows and Mac that make you productive. I can say this with certainty as someone who hasn't used Windows for almost 15 years and has never used MacOS. When I come into contact with those systems I have no idea what's going on. Windows has a million buttons all over the place and MacOS has really weird, unintuitive behaviour and "gestures" that you need to just know, somehow.

The best way is just to take the plunge. Immerse yourself by removing other OSes from your own PC. In a few weeks you'll be flying.