I would like to know if you do touch type. Touch typing plays huge role in keyboard experience imo.

In my experience, linux has the most ergonomic shortcuts (combination of windows and mac - linux mint with cinnamon desktop) with little bit of customization. If you have a habit of not touching mouse much, honestly linux rocks.

Mac has few consistent keyboard shortcuts but you can't operate system without mouse/touchpad. And for many keyboard shortcuts, you need to press awakwardly 3-4 keys simultaneously.

Windows has some good shortcuts but it is not designed to use by keyboard soley. Focus seems more on mouse.

Also I would highly recommend mechanical keyboards. You can configure good amount of shortcuts using control key and press it using your palm.