Alt Drag move/resize window with mouse and modifier key Alt±Shift

Have you tried adding "Activate/Bring to Front Window Under Cursor" action before resizing?

Personally I could not achieve similar behaviors to what I had on XFCE linux :
The resize here is always starting from the bottom right corner while I would prefer the closest corner to mouse.

Also I had the "Fill Window" behavior on Alt + Double Click where the selected window would try to fit as much space as possible until it reaches other windows border.

So for now I've setup double and triple clicks with option modifier to place window to half or thirds of the screen and that's good enough