Me who uses KDE default

On linux, generally everything you install is through a centralized repository, you can think of it as an app store, arch is all entirely updated through pacman, pacman is just a command line way to interact with the app store.

In general, almost everything you install with pacman will update when you do pacman -Syu (and restart, in case of kernel updates). The way packages work, all the files needed for a piece of software to function are installed from a package, and when you install a newer version, it removes all the files from the old version and puts in new ones. (Caveats apply to configuration files you can modify - those don't get replaced if you do)

So after you update some software through pacman, it should be in an entirely clean state, just like if you just installed it. The main caveats apply to things like flatpak, which manage its own packages, and software like Steam and Discord, which have an additional auto-updater for some things that's storing files separately.

With Arch pacman -Syu will do it for you. Generally you are encouraged to stick with the version in the repositories.

You can install things from source by downloading the source code, building it (eg. gcc code.c or cargo build) and then copying the binary somewhere.

Typically if you were going to install things from Source, you would write a pkgbuild for it and that would integrate it with pacman so you have a centralised manager of everything that you have installed to simplify updates and removal and conflicts etc.

Doing this for small packages is pretty trivial and sometimes necessary. For a large package like KDE plasma It is a very large undertaking and you would never do it in practise.

The maintainers package the desktop environment with a pkgbuild, test it, And then upload it so that you can use it.

Also note that when the arch maintainers do package that software they compile it into a binary so you just have to download it. You don't also have to build it.

I am not sure if anyone answered your question in a way that you were expecting so let me try

yes you will get the update but you might not know it because your config wont change, so you have to go into the theme settings and use the "default" to see the pretty

New to arch and new to Linux:

Install a yogurt, or yet another one!

You update and then the entire system breaks (because Arch)

I don't even need to install any new packages to get that

sudo zypper dup

992 packages to upgrade, 2 to downgrade, 18 new, 3 to remove.

Package download size: 1.81 GiB

Half the packages are LibQT6something or LibKF6 something lol

Yeah that drives me nuts, it's like I'm installing a flatpak

Gnome on Debian is fairly out of date. I personally like all the new features.

However, I think it would be cool if you could run Fedora with gnome in Podman. Solid base with containers for newer stuff.

I was running MATE door years before switching to Windows 8.1 and shortly after first public beta of Windows 10 when it was available. I was even helping translating it to Polish for like a month or two, but given that I was probably like B1 (about B2 right now) in English at that time it was probably not ideal, lol.

What dinosaurs of a computer are you using?