I had a problem where when I put any disc in it would chug a bit then sound like the disc was being relocated then chug a bit more. After this I’d get a pop up saying unrecognised disc.
I tried many things. First I tried completely dismantling my pro to get to and clean the disc drive lens, but it already looked pretty clean and that didn’t make a difference.
Secondly I tried forcing my pro to update in safety mode to rebuild the database as I heard that could help, but again it didn’t.
Next I began messing about with applying pressure above the disc drive with my hand (squeezing the front and back together) as I inserted the disc as some people suggested knocking on the console. This did help often but not 100%.
Lastly I changed my PS4’s orientation, I have mine vertical by default as I have limited space. I changing it to horizontal, this didn’t really help. But turning it upside down vertically 100% fixed my problem. It now reads discs quickly and quietly 100% of the time! I can’t believe something so simple and honestly a little bit stupid has worked so well. Give it a try yourself!