Have you considered adding focus-follows-mouse to Rectangle or Rectangle Pro?

[snarkmaster]

As a Linux person forced to use a Mac, I'd find a sloppy focus implementation quite valuable. I found a version in https://github.com/sbmpost/AutoRaise, though I haven't made time to build & try it yet.

On the other hand, Rectangle is already making a tangible difference to my workflow. Thanks for that!

[rxhanson]

Thanks for asking. I'll be honest, I tried that feature out a long time ago on another OS and did not like it. With enough demand, I'd consider it.