It's possible that's your monitor profile has an error.
Do you tried to install an older version of your graphic driver? Sometimes the newest drivers are buggy.
This is for lightroom classic.
I did a clean install of latest nvidia driver for GTX 1080 graphics card and am still getting this issue.
Basically exporting slideshow to video is greyed out.
What makes you conclude it is the video driver causing this?
Going back to the previous driver worked.
Nvidia had installed the new driver on may 26th.