I didn't like the scroll area of the building slots in "Newer Better Buyable Building Slot + Infinite Building Slot" mod, so I went into the gui and changed the display to be similar to the “Extra More Building Slots(16 slots)” mod, as well as making another custom display.

Installation:

Drive Google[drive.google.com]

Download and replace the “window_county_view.gui” file in the .../2891294108/gui folder with one of the suggested options.
If installing gui only, edit the file by removing the widget containing the part from “ ### ADD BUILDING SLOT ###” to “### end ADD BUILDING SLOT ###” in 4x1 and only that part in 5x3.

If you want to update to a newer version of ck3 or set this gui to another mod, then in those files, move the lines labeled “CHANGED” and the lines between “START CHANGED” and “END CHANGED”.

Modification:

If you want to increase the number of slots at the beginning of the game as in the “Extra More Building Slots(16 slots)” mod, copy the defines folder to .../2891294108/common. In the file “zzz_defines.txt” you can edit the number of initial slots.