The trouble is it's difficult to get any objective data on this. Catalina has been rock solid for me. So is this a problem for a handful of noisy individuals or is it more widespread? I really don't know.
I have been upgrading (and porting to new machines) a Mac account starting in 2008 on a white macbook (2006?), transferred to a 2009 iMac, and then transferred to a 2017 iMac. Never had issues until Catalina.
Catalina finally made me do a completely fresh install with transferring data files as the only touch from the old system. Since the fresh install, it has worked perfectly, but before that the system would randomly keep repeating the last typed character. I could not live with that behavior.
Also got a new MBAir 2020 (Catalina) and that has been perfectly fine and solid as well.
This is exactly where I am right now and I’m starting to explore my options for jumping to Linux for desktop and laptop. There are some great distros out there that I’m looking forward to trying.
I'm more or less in the same situation. I own a 2013 15" MBP that still works perfectly but I'm afraid of what will happen if / when it stops working. I actually use it often, so it could get stolen / I could drop it / etc.
My client uses Windows and HP computers. I've been able to save an "old" Elitedesk 800 G2 SFF (6th gen i5) from the dumpster and upgraded it with an old ssd I had lying around and 16 GB of ram (instead of 8). I've set up ArchLinux on it with I3 and boy do I love that machine. It's plenty powerful, quiet, and everything just works. It actually replaced my MBP as my "dev" machine during the WFH phase.
I've also had close to no issues running Arch on a Probook 430 G5. Everything except for the fingerprint reader works. But while the desktop is great, I'm less happy with the laptop. It's not so much related to Linux but to the physical machine itself (the touchpad isn't great, the keyboard's texture feels weird, it has coil whine, assembly is half-assed and rubs the wrists while working on it, etc).
As they say, YMMV, but my experience is that depending on what you do day to day with your computer, a Linux PC may actually work surprisingly well compared to a mac, especially on the desktop where the superior materials and assembly of the mac are less of an issue.
I find desktop Linux much better as a developer OS than my MacBook. Now if only there was a good ryzen laptop with amd gfx I'd be up offa the Mac entirely.
So, when I buy “new” hardware, I will make sure that it is compatible with Mojave.
Which means it won’t actually be new....
Something’s wrong when the best hardware you can buy from a manufacturer is from the versions they’re not making any more.