I use Arch but you are kinda over zealous about how good AUR is. It is completely unmoderated and, as others have said, a security risk. But it can also pretty easily bork your system because of a bad package. I don’t know how long you’ve been using Arch but it’s only a matter of time before you’re pulling your hair out trying to fix a broken dependency.

Arch is also not the only distro with giant repositories. Void has a pretty massive repository but it’s better moderated. The Debian universe is just as big if not bigger but you have to add repositories, it’s not as central. Same with the Red Hat world. Arch just dumps it all in to one chaotic bucket which is very convenient but there are downsides.

Fedora has a pretty good amount of software in the repositories, so a lot of the time that's enough. When it's not, flatpak with flathub have most gui software covered, and outside of that, if we're talking about terminal or command line stuff, most of those have their own custom way to install them, or they just have self contained binaries that you can put in ~/.local/bin/.

I haven't run into many issues with flatpak like it sounds like you have, so that really covers a lot of it for me honestly.

80% of the time, compiling something from source is just a matter of downloading the code, opening a terminal and changing to the directory containing the source and running these commands:

./configure
make
make install

It's the same 3 commands, 80% of the time.

Installing the prerequisites can be tricky, if the docs are lacking.