I don't know what "Serato DJ Pro 4" is. But I'm using Serato DJ Pro, and there are options for displaying either 2 or 4 decks at once. However I'm using 2 decks mostly and find 4 decks display are quite crowded as you CANNOT adjust the sizes of areas in Serato.

Up near the top left you have some options for how the view is arranged. It is limited, but you can browse through the drop down lists and select what works best.

I wish there was more customization and adjustability. I'm using a 22" touchscreen, and I still think I would resize and move things around.
There is also a "compact" variant, but I found you lose access to some things and it's very cramped. So I stick with the standard 2 deck at this time. I find if I'm using 3 or 4 decks, it's probably for some background, so it's easy enough to switch back and forth from the dj deck. And luckily this is done individually 1/3, and 2/4; not 1-2, and 3-4.

Thanks.