Screen Replaced, very dark at full brightness

Hi, I've recently replaced the LCD screen assembly on my 2018 MacBook Pro with 4 thunderbolt ports running Ventura 13.2.1 currently (A1989 model EMC:3214) after the previous screen was showing purple bars along the whole screen.

The new screen is very very dark even at full brightness while in use. Bringing the brightness slider to about halfway just turns the backlight off completely too.

Ive tried SMC reset with no success, and also NVRAM reset through multiple methods. Interestingly enough, after the NVRAM reset... the screen does go to full brightness when booting up but when about a third through the progress bar during boot... the brightness goes right down.

I've also attempted twice to remove the display again and reseat everything, with no success. Have even tried unplugging the battery connectors and reconnecting them.

If anyone could help, it'd be much appreciated cheers