Think about how long CD players have been in production. It's not new technology. DAC chips have been produced for decades. The line out from most players will be identical because it is mature technology. As TLS Guy mentioned, there are only a few suppliers of laser pickups. I have watched a lot of CD repair videos by Spare Time Repair and the expensive CD players use the same Sony or Phillips, etc. pickups that the cheaper players use. As long as it tracks without skipping, it's fine.
If you are using line out, the only comparison to make is between DAC chips, but finding out which DAC chip a player uses can be a chore. And then you have to research which DAC chips were poor performers and which are rated highly. There are a lot of different chips out there! If you can use the COAX connection then the point is mute as the AVR DAC takes over. And if you use any digital processing at all (which is pretty much any mode that is not Stereo Direct or Pure) then it gets converted to digital, processed and then converted back to analogue by the AVR DAC.
Blue-ray players are a good choice because they support all formats and the tolerance on reading blue-ray is much tighter than CDs, so any blue-ray will play CDs perfectly. And if you stick to one of the popular models recommended on the forums, like the Sony, they come with decent DAC chips any way.
Personally, I think it's much ado about nothing. The crappy DAC chips are few and far between and few would ever notice the difference between those and say the top ESS Saber DACs. And if you use any digital processing in the AVR, the AVR's internal DAC has the final say in the matter regardless.