Mate look this is Software Manager underlying of it is apt.
Selection_001.jpg
When you update, apt checks your collections of packages first.
Then look thru repos if there are updates, then update once which got updates.
To make it simpler lets use numbers.
Lets say you have package1, package2, package333, package4589, package5555.
Lets say package333, package4589 have newer versions in repos then ones on your PC.
So apt will download them and fetch them for you.
Apt is a robot, it is not concerned if you need, use or what you do with your packages.
So you can have entire KDE desktop installed which you don’t use and never open.
If KDE packages will get updates, apt will update them too.
You don’t need to uninstall anything just update.