Mentioned elsewhere, but KWM may be a little more to your liking and focus follows mouse: https://github.com/koekeishiya/kwm
Amethyst has an experimental focus follows mouse. Does KWM handle modal dialogs a little better than Amethyst in that mode?
(I will also say that macOS's menu bar app buttons were not designed with focus follows mouse in mind!)
https://github.com/ianyh/Amethyst