Earlier quoted context omitted.
I got a Windows PC for the first time in over a decade recently and I cannot understand why MacOS updates are so damned slow
Because on newer Macs, it’s rewriting the whole OS partition with a new firmware image, much like iOS and IPSW files. Windows, on the other hand, generally does incremental upgrades.
Coming from Windows and Linux, macOS had been a very unpleasant experience for me. It's full of papercuts.