If i got a beginner friendly distro how will i learn how to use linux properly?

That’s like asking how will you learn to swim if you start in a pool where you can reach the bottom. First of all under the hood Ubuntu and Gentoo are 99% the same, the main differences are philosophical, almost everything you learn for Ubuntu will carry over to any other distro. But if you try jumping straight into the deep end you will be overwhelmed. I mentioned Gentoo because you usually compile your own kernel when using it, how can you possibly learn Linux without compiling your own kernel!? But the majority of people who know Linux nowadays have never done so, and you shouldn’t need to either. The same applies to all the thousand paper cuts you’re inflicting to yourself for choosing a distro whose philosophy doesn’t include being beginner friendly.

So if an app is not a package manager i’m fucked?

For the time being, yes. But here’s the thing, if everything else is working, figuring out how to install a package manually is simple, but if you’re struggling with 100 other things you will be overwhelmed by it. Tell me, when was the last time you downloaded an .APK from a random site on the internet to install something on your phone? It’s the same thing.

I tried, it did nothing, i went online to search for a solution.

Weird, that used to work last I used Debian based with KDE.

This is mental. This shouldn’t be a thing even for pros. I need 15 minutes to install an app? Sorry i won’t go out this evening, i need to install an app and god knows what can happen.

Nope, I could install that in 1 min, because I know what I’m doing, so I know how to install dependencies. But you don’t, so you shouldn’t try to install stuff manually. For starters I would have added a PPA instead of manually installing a .deb, that way the package would get updated and apt would install the dependencies automatically, if that wasn’t an option or I was feeling lazy I would have just installed using snap/flatpacks, or if I had to install using a .deb, I would just use apt to do it to autoresolve dependencies. The fact that half of what I said there sounds like gibberish is the reason why you shouldn’t do it. It’s equivalent of someone who can’t even use Android properly asking you how to install an APK not on the play store, first learn the basics, then you can do complex stuff.

Well, yes, of course. Also i read some contradictions in your post:

No contradictions, let’s go over one by one

the installer only installs what is supposed to, but it needs dependencies to actually make the app usable.

Yes, but each dependency is its own package, so when you install one package you might be installing several. But if you try to install one package manually (via dpkg) you don’t get the packages it depends on (because dpkg is a glorified unzip, it doesn’t know how to fetch dependencies).

But that’s what package managers do, right?

Exactly, unlike dpkg, apt does know how to install the dependencies, so it would do it automatically.

Different apps could use the same libraries but also different ones, so the system could become bloated nonetheless.

Yes, but you’re missing the point, a single library doesn’t weight that much, a dozen copies of that same library do. You installed KDE, so you probably had these apps (among others):

• Dolphin
• Okular
• Kwin
• Konsole
• Ark
• Kate
• Etc…

The KDE library is 150/200MB, so on Windows each of those application on it’s own weights at least 200MB, so probably you’re looking at 2GB for 10 apps that use the KDE library. On Linux they weight very small amount, because all of them use the same KDE library which is installed system-wide. Maybe some of those also use other libraries, but if you install anything else that uses that same library the library won’t be duplicated the same way it is on Windows, where each installer is self-contained and brings all of the libraries it needs to work.

I don’t see how is this beneficial for the user.

There are two main advantages:

• Smaller footprint for the system. Like I shown installing all those packages on Windows would be a few GB, but on Linux it’s probably less than 1. Expand that to an entire system and you’ll see how you can have a full Linux system filled with packages occupying less than Windows with some programs installed
• System-wide updates. Imagine a vulnerability was discovered in SSL, on Windows you would have to manually figure out which programs use SSL, figure out if the latest version of it uses an SSL version that fixes that vulnerability, update them to that version, rince and repeat for all programs installed. Whereas on Linux a system update fixes everything. Same thing for new features or bug fixes.

And the disadvantages are:

• Complicated to install a package (because you need to resolve the dependencies). Which is not an issue if you use a package manager.
• Stuff might break if different programs depend on different versions of the same library. Again, not an issue because the package manager ensures everything is up to date so you get the latest for all apps and libraries which work together, but the moment you install something manually you need to manage this manually for that package.

So overall it has 2 huge benefits and no downsides as long as you use the package manager.