Organisation is daunting as fuck

Read up on modules. It's obvious you haven't even googled it.

I've heard home-manager is good, but I don't really get the point of it. What does it achieve for me that editing configuration.nix doesn't?

1. You're not supposed to use configuration.nix for userland packages. Separation of concerns, and so you don't need to rebuild all the time.

2. Declarative package management and configuration

3. You only need to remember one command to install and update all your packages

Installing software feels like the roll of a dice

There are many ways to install a package, and that allows you to chose the one you want to use. Nobody's forcing you to use the module instead of just the package...

And now there's Flakes too. I'm sure they're great, but right now I just see them as yet another way to install software on Nix. Great.

You don't use flakes to install packages. You use them to control the package definitions, pin specific versions, add packages from outside of nixpkgs in a declarative manner, and so on.

I really want to like Nix, but it's not making it easy.

You really want to like Nix, but don't want to learn basic concepts and instead expect it to behave like every other distro.

If installing packages is too much for you, give up on nixos and use something else. That's literally the easiest and most issue free part of using it. You can install hyperland through nix on Debian or whatever distro you want.

does not feel better than apt install or pacman -Syu etc.

Yeah, why would anyone want a list of packages they currently have installed. Can't think of any benefits, nope...