I use https://rectangleapp.com/pro and really enjoy this app (I paid for it, it gets a lot of updates/fixes).
It mostly takes care of snapping and resizing windows with hot keys, but has a less obvious feature in preferences to use mouse.
My setup is: CMD+SHIFT will move any window under mouse pointer CMD+SHIFT+CTRL will resize any window under mouse pointer
Wow, I didn't know there was a paid Pro option, but the same developer also makes the open source app Rectangle, which sounds like the same thing minus a few features. I use it daily. https://github.com/rxhanson/Rectangle/