Dividing my screen into a grid?

[lsquare]

I'm wondering if there's an app that can create multiple windows in a grid. I want to have multiple web browser/word processor windows evenly divided by pixels in a 4x4 grid on a 4K display. When I go full-screen in each of the windows, it'll only be full-screen within that window, if that makes sense. If possible, I want macOS to reboot or start into this setup until I disable it. Anyone here know how to do this?

Thank you!

 

[Fallforward]

Hover your cursor over the top-left green dot. If grid choices come up, pick the bottom right. However, it does not save for reboot.