I come at this from a completely different viewpoint, having only recently dipped my toes into Linux - for me, a package manager is a relatively new concept. The nearest I've come to it previously has been with Apple's App Store, both for iOS and now OSX - plenty of choice, sometimes too much choice.
As far as manually installing apps goes, it usually boils down to double-clicking on the DMG file to mount it, then either running the installation package or dragging the app file to your Applications folder.
In theory, uninstalling apps is as simple as dragging the app file to the Trash. I say 'in theory' because apps do leave behind some detritus formed by using them - thankfully not to the same degree as Windows, but it is there. For suites of apps like Microsoft Office or Adobe Creative Cloud, there tends to be a lot more extra stuff deposited onto your system besides the apps themselves.
Sadly, updates do tend to be on a per-app basis, with the exception of those acquired through the App Store, which handles the update process.