Ah! It appears while that isn’t a default shortcut in GNOME, you can kinda get that by setting the Resize Window shortcut under Keyboard -> Shortcuts -> Window menu.

It’s a bit wonky if you want to resize it diagonally, as it moves the cursor to the center of the window, and then whichever is the first direction you drag the mouse is the edge it snaps to in order to start resizing. Works perfect for top/right/bottom/left, but if you try it diagonally then often it gets one of the other directions instead.

I will however have to remember that shortcut for when I’m on other DEs!