On my 2019 MacBook Pro 16" I replaced the display cable to bring my camera and keyboard backlight back. Patience needed, logic board has to come out for this repair. I have read in a number of posts that the T2 chip is the issue when replacing the screen and have encountered that on other Macs but found one fellow who recommended changing this cable out and it worked for me! Here is the iFixit part, MacBook Pro 16" (2019) Display Cable
I have replaced the 2019 27" lcd with both a 2017 and a 2020 27". Easy swap with the 2017, the 2020 required modification. The camera is built in to the 2020 lcd instead of being mounted on the body chassis as on the 2019, thus a tricky mod. I removed the camera from the 2020 and then used a Dremel to grind out the camera housing, being very careful not to damage the glass next to the camera or to grind past the plastic camera housing into any circuitry. This made room to place the 2020 lcd on the 2019 iMac and simply use the already mounted camera on the 2019 chassis without further mod. I did lose the True Tone function with the replacement but otherwise the 2020 lcd on the 2019 works perfectly.
