I've started[1] to do similar things on macOS using Hammerspoon[2]. So far I've set it up to let me:
1. Use shift when pasting something to simulate typing in the text instead, getting around websites that block pasting.
2. Use ";" as a hyper key. By holding it down and pressing another key, I can switch between specific programs without cycling. I can also use hjkl as arrow keys.
3. Automatically switch audio input and output devices according to my specified priority order. Because macOS would frequently get it wrong, including treating my monitor as a speaker for some reason (it doesn't have built-in speakers).
4. Make control act as escape when tapped. I use this in conjunction with remapping caps lock to control in macOS system preferences. I previously used Karabiner Elements for making caps lock work as escape when tapped and control when held, but I was able to uninstall Karabiner because Hammerspoon was sufficient.
5. Disable the insert key because I've never wanted its functionality, but I would sometimes hit it accidentally.
[1]: https://github.com/dguo/dotfiles/blob/master/programs/hammer...
[2]: https://www.hammerspoon.org/