Re: grey screen in CAS
@mimzyy As a test, please try playing in a clean user folder. Move the entire Sims 4 folder out of Documents > Electronic Arts and onto your desktop, and when you launch the game, if it launches, a clean folder will spawn with no content. (Your saves and other content will be intact in the folder you moved but temporarily not read by the game.) Don't add anything to the new folder yet; just let me know whether you can get far enough to start a new save and play in live mode for a bit.
If this works, you can move your saves and anything else you'd like to keep to the new Sims 4 folder. But test your mods and custom content first, in case one or more of these files are the problem. Leave your saves for last, after you've tested everything else.
If you see the same issue even before adding any content to the new folder, please run a dxdiag and attach it to a post.
https://help.ea.com/en-us/help/pc/how-to-gather-dxdiag-information/