I installed a new xbox one X disc drive and it won't read discs

It actually does. I got the Series X this holiday at $349, and the same disc is working perfectly. I have determined that the Xbox One X disc drive is trying to read Cross Gen discs differently than Xbox One discs. The disc drive on the Series X doesn’t have this issue. You might need a new disc or you might need to send your Series X for maintenance.

We cannot assist with self-repair.

Have you tried installing the game to your hard drive? Look at the bottom of the screen on the dashboard and press the button for more options on the disc (Y or X I believe) then choose install disc. After that you'll only need the disc in the console
but it won't read from it when you play.

I take it Blu-Ray disc movies are working okay? Have you tried many of the ones you own? Games are detected?

Bear in mind that the Xbox One S, One X and the current Series X actually have two lasers, one for reading DVD discs (including Xbox 360 discs) and one for reading Blu-Ray discs, which also includes Xbox games as they are also on BD-Disc.

If the DVD laser is giving out, it won't read certain DVD discs, and this is likely the reason for the issues you are experiencing. This is also why Blu-Rays and Xbox One games are not effected. There is nothing wrong with your DVD's, it's the console's optical drive that is faulty.

Try installing the game to your hard drive. With the disc in the tray on the home page of the dash, press X for Game Details then choose Install. You'll still need the disc in the tray but the game will be read from the hard drive instead of the disc drive.