Mojave wasn't perfect (I got a gray screen every few months or so), but Catalina has been measurably less stable on the same hardware, same monitors, same peripherals, etc. to the point where (as stated by others) I can't even safely sleep/hibernate with external monitors connected anymore.

Even if it were a hardware problem that Catalina somehow tickled more often, if it only affected 5% of users it's still a problem. Being one of the lucky 95% doesn't diminish the experience of the 5%, especially if with Mojave the affected user base could have been 1%. We're not talking about $200 Chromebooks. These are $3K+ professional tools.

Bottom line: Catalina is less stable than Mojave.

The common experience is yours - and mine. I’ve had minor problems with Catalina, mostly around slowness and my 2014 iMac 5k randomly sleeping from overheating (which might not be Catalina, might just be dust).

I use it heavily 10+ hours a day and the only problem I’ve had is my windows are sometimes resized when I wake it from sleep. Bug related to using an external monitor.

I'm sure many people haven't noticed any problems when using WD's SMR drives in a RAID either. Does that mean there are no issues with SMR in RAID or that it is insufficiently common?