As a free alternative (which I use daily) I would recommend "Hammerspoon" https://www.hammerspoon.org/

You will need to do a little configuration, but it does the snap zones thing perfectly.

Just coming across these. I've been using amethyst. Would this offer any benefit to me ?

Hammerspoon has the benefit that in addition to managing your windows / spaces, you can also script tons of other things in the macos interface with it: have a glance at https://www.hammerspoon.org/docs/ to see the top-level modules.

been playing with this all day. This thing is amazing. Thank you for recommending this.

> If you use a Mac, I’ve really enjoyed using Divvy. You can define snap zones with keyboard shortcuts.

My memory is hazy but I feel this is close to some now-elided window management feature in MacOS...

Thanks for the tip!