I use easy-move-resize [1] to resize windows from anywhere inside the area of the window, using a modifier key. In my case I like using cmd + middle mouse button + drag.

This is standard in Gnome and a must for me back when I switch to MacOS for work.

[1] https://github.com/dmarcotte/easy-move-resize

Just tried this. Pretty cool. Kinda strange how the mouse cursor doesn't move with the window, but still might be worth using.