> Package managers on Linux work better than brew IMO. They are more mature and better integrated with the OS.
Brew is more than Brew because of Brew Cask.
More mature, how? Can you already install multiple versions of a package with Linux package management? From what I read, NixOS comes close to the way Apple works with .App. Debian and Fedora don't use that. Don't get me started on Debian. Stable, yet always out of date.
macOS is also UNIX while Linux is Linux (and has Systemd which I'd have to learn, while for example Launchctl I already know). macOS comes with PF (which I know how to use and is much easier than IPT), and a Little Snitch license is only 30 EUR. Then there's X11 and Wayland. Is Wayland default already? I don't know.
> It would be nice if brew upgrade installed OS security patches etc.
softwareupdate* allows that. If it bothers you to type, make some shell scripts. Not a big deal. You even see they're available in the Dock.
My main gripe with Brew is Brew Cask. I need to check with a shell script if the closed source packages have been updated. But on Linux I'd be using APT repositories or would have to check manually as well.
Windows has Chocolatey which is nice, but like I said you notice Windows isn't UNIX all the time (tho it has improved, and so is Microsoft!).
> I found it easier to rebind keys in GNOME than Mac OS.
You don't get it. I don't have to rebind much. The default are consistent, logical, and useful already. I don't use Spotlight or Siri so that is disabled. Alt + Space leads me to iTerm (with Tmux), and Cmd + Space leads me to Alfred. Caps Lock is bound to Ctrl. The rest is default.
When I looked for Linux notebooks the price of a MBP 2015 was slightly higher (while there was an in between 1080p and 4k) but then I know I don't have a learning curve, and the above advantages also remain.
Finally, my gf can use Microsoft Office on my MBP if she really has to (I don't use it myself). I tried to get her to LibreOffice but there's a learning curve involved and we both CBA.