Physical degradation of CD's

The laser will not degrade the CD.
Some CDs get rot as mentioned above.

The only concern I would have would be that it might be getting hot inside the player, and leaving a CD in a hot place for a long time can cause it to delaminate (rot).

Find something else to worry about.

None of my pre-recorded/store bought CDs have degraded unless scratched or otherwise damaged.  The CD-Rs that I burned have shown substantial degradation somewhere in the 50% range.  CD-Rs contain inks while pre-recorded CDs don't.

If you’re still at all concerned then just use a cd of music you don’t really like and don’t care if it’s damaged. You must have at least one of those in your collection. 

Just know that the "energy" of the laser reading the pits and spaces is nowhere near the energy that was used to create them. So, no, you can play a CD a million times and it will be just as good as the first time. This was indeed one of the "selling points" for CDs compared to vinyl album back in the 1980s.

I would worry more about putting unnecessary wear and tear on your CD player in breaking in the new DACs and use a streamer instead set on various playlists that run for hours and hours. 

Regarding "CD rot", I have a collection of about 2500 CDs, some from the mid-1980s. Out of all of those I’ve had TWO "go bad" because of oxidation of the aluminum substrate. It was like a small pinhole was somehow created (either a manufacturing defect or caused by rough handling in a car). Fortunately, I was able to find copies still in print and simply bought replacements.