I had no issues. I have iTunes Music Match as well and:
- I completely wiped out my 2014 MBP's SSD and installed Catalina clean from a USB key. I transferred my profile to it wayyyy back on Yosemite -- when the MBP was new -- and have only updated ever since. I had a TON of legacy apps and leftover crap that I didn't need, and felt Catalina was a good time to start fresh. Music.app immediately pulled my entire music collection's pointers and then slowly began to download the matched tunes.
- My iMac hosts the "real" library (i.e., 320kbps MP3s and the like); I updated it from Mojave, and Music was just fine.