I've having a feeling that iOS 13 & Catalina is felt buggy b.c. it's not the operating system itself that's buggy but that the updater is buggy. Many things have changed in this release, and the installer/updater had to handle too many different scenarios.
For example, when I upgraded from Mojave to Catalina, an 'Moved Files' directory appeared that contained some files (that was once) in /usr/local/. I don't remember such directory appearing after an macOS update, and I've had many friends (that aren't really technical) appear that to them. There were lots of new applications (like Music.app and Podcasts.app), and data migration between internal databases weren't perfect.
I've installed Catalina two times, first by upgrading from Mojave and second a clean re-install.
When I upgraded Mojave, I found too many bugs that I was worrying about data-loss, which lead to a full backup (I do backups regularly) and a clean re-install. (Admittedly, this was my first clean reinstall for a major macOS update)
I clean-installed Catalina and manually restored all of my files from the backup, and except for some minor bugs I'm good.
It's a pity that updates aren't seamless, but if there's anyone having trouble with various Catalina bugs, (while Apple updates it's imperfect macOS updater) I would recommend a full clean re-install for macOS Catalina.
Even with SIP disabled you can't do shit to that volume until you remount rw (at least, this was reported to work in betas, haven't seen anyone test the shipped OS).
Huh, I definitely have some moved files, and they're definitely from homebrew. But you're right, they're not from /usr/local. Perhaps the OP made the same mistaken assumptions of origin as I did?
I second the full clean reinstall. I encountered some very strange and show stopping bugs (Dropbox refused to work even with a reinstall for example) which disappeared after a backup and clean install.
For example, when I upgraded from Mojave to Catalina, an 'Moved Files' directory appeared that contained some files (that was once) in /usr/local/. I don't remember such directory appearing after an macOS update, and I've had many friends (that aren't really technical) appear that to them. There were lots of new applications (like Music.app and Podcasts.app), and data migration between internal databases weren't perfect.
I've installed Catalina two times, first by upgrading from Mojave and second a clean re-install. When I upgraded Mojave, I found too many bugs that I was worrying about data-loss, which lead to a full backup (I do backups regularly) and a clean re-install. (Admittedly, this was my first clean reinstall for a major macOS update) I clean-installed Catalina and manually restored all of my files from the backup, and except for some minor bugs I'm good.
It's a pity that updates aren't seamless, but if there's anyone having trouble with various Catalina bugs, (while Apple updates it's imperfect macOS updater) I would recommend a full clean re-install for macOS Catalina.