I'm curious how you arrived at some of these conclusions.
- Sluggish UI -> I've never experienced this in the last three years of using my 2017 MBP.
- Inadequate package manager -> Somewhat nebulous, most package managers on Linux are available on Unix.
- Slow and large updates -> I honestly don't pay much attention as I have updates install automatically while I'm sleeping, but what size differences have you noticed?
- Slow boot to work -> Never experienced this, boot is less than a minute regularly.
- Can't have a minimal desktop -> Beyond hiding all icons and the dock, what more are you looking for?
- High memory usage of base system -> Never seen this come close to the main applications I use on a daily basis. What quantified results are you receiving to notice this?