The first couple of Catalina releases were a hot mess—my Apple USB keyboard refused to work reliably; I could only use the Bluetooth keyboard that came with the iMac.
By the time we got to 10.15.7, it was rock-solid.
I've been running the release version for a couple of days now and it's been rock-solid as well.
10.15.7 has been very stable for me, on my work laptop I reboot maybe once a week or so and a lot of the weird thunderbolt issues have been resolved (I think 10.15.5 or 10.15.6 IIRC).
If you're running an external display alongside your primary display, that could be causing a graphics memory issue. I had to tweak some display settings and it went away. Most system crash messages are pretty-well documented online.