I don't understand what the heck you guys are all complaining about...
My Mac Pro is from 2013, my wifes MacBook Pro is from 2014, my daughters MacBook is from 2016, and our entertainment center Mac Mini is from 2018, and they ALL run 10.15.4, and they are ALL running perfectly. No issues whatsoever. I use almost all the Adobe CS applications, in addition to O365, Parallels (for gaming) and the usual apps and utilities. I didn't even clean install, but have only upgraded the last 3 years. My wife is using O365 and a range of educational applications, and have no issues. We both leave our Macs running for days at a time.
What I trying to say is; perhaps it is not the OS, but rather your particular installations?