My 2 cents re. the OP:
Have set up my MP7,1 in the last week or so, migrating material & hardware from both a MP5,1 and a Dell T7910 workstation (still keeping and using the latter in parallel to the MP7,1). Two things: Catalina is a dog IMO; the MP7,1 hardware is brilliant - no doubt will receive design awards in the future and end up in MoMa I'd say.
The hardware has been fuss free, fast, silent and takes everything I throw at it - PCIes, external drive bays, a bizzillion USB devices via hubs, external Displays that are not Apple, etc, etc, etc. Most of the ports are maxxed, no bus load issues; external pro audio IO, BlackMagic Decklink and so on. Such a great piece of tower here. For context, the overall usage is in a multimedia recording studio with pro audio and film hardware & software. It patches into the room perfectly.
Catalina on the other hand .... where does one start? And also in mind that the 'Apple tax' starts here with the embedded cost of a very expensive OS.
I guess the main thing to whine about is in losing so many applications /audio & video plugins & other bits and pieces. And this is not a 64bit vs 32bit thing. It is just plain 'won't work' anymore. For example, earlier version of Pro Tools (2019.6, not 'that' early) or Waves v9. Now these could be upgraded to the very latest versions, but that also costs a bomb, don't need ... In the case of Windows 10 for Workstations (ie, the 'pro version') - all of these apps continue to run and function perfectly.
Ditto for some AU plugins - simply will not be recognised by the apps that need them (a bit silly because AU is simply a Apple propriety wrapper on a VST plug). That's fine then using VST3 with apps like Cubase, Ableton Live, DaVinci Resolve etc, but for the Apple apps Logic & FCPX, some of this is clearly a dead end.
Still have not got to the bottom of all that re. software installs and interdependencies, but my general takeaway is that I have to learn to live with not having some of my software (and longterm investment) not being available anymore. For that I keep the Dell & still prefer the UI and OS control over the rather awful Catalina.
So, all the above should even more strongly support a 'clean install' process, but in my experience, also you really need to pay attention, & to hunt & peck & test throughout the process because of Catalina.