So, I've noticed that some people have experienced the same bug as me: Tiny portatraits and room size.

I've found a way to manually fix the bug for the portraits but I've not tried for the rooms (basically because I don't care about the rooms) so if you found a way to fix the rooms sizes post it here, might be useful for some people.

So to fix the portraits you have to find where the .zip of your mod is.
For me it's here:
Whateveryourdisknameis:\SteamLibrary\steamapps\workshop\content\281990\682190594

Here, open the .zip then go at:
gfx\portraits\portraits

Open the .txt file and change things like that:

character = {

#2d Portrait position
icon = {
orientation = center_down
position = { x = 240 y = 0 }
scale = 2.0
}
}

(Basically just change the size to 2.0 and the x position to 240)

Now launch the game and your portraits should be at the right size!