I’ve had to remove the BTT screen so I could have a functional screen. I reinstalled the original and it works just fine.
This has confirmed my suspicions that I simply do not need these screens.
I have installed the BTT screen on another printer (not enclosed) to check if the same issue shows up, and so far it seems to be working.
However, it is connected to different mainboard (not SKR v1.4) – And to note, I have same serial setup in Marlin on all my BTT boards.