Using established System tools

Not an option for me. They create a 100 problems and solve only a couple.

Yes. Documentation is one of the biggest & most glaring issues with NixOS. When just glancing at the manuals & official resources, it seems like plenty is there, but compared to the vast amount of configuration that needs to be done in NixOS, the actual amount of documentation is really minuscule. It barely touches the surface on most features.

Especially the recipes are pretty terse, too specific to a certain scenario & very reduced.

I really prefer to follow best practices. I do not like dirty workarounds.

Where is that mentioned in the NixOS documentation?

If that would be my goal, I wouldn’t have set up NixOS. I do everything by configuration. But that does not mean, I’m going to take the time to write a huge module for every single thing that exists out there. This would take loads more time than just reproducing an imperatively built generic operating system.

Not sure, what you mean. Also, in case you missed it, I don’t want to use Grub Customizer. It was just an example. I do my GRUB configuration manually.

When it comes to other things, there is sometimes no way to have an “open mind”, if there is only a single solution to a problem, like for example, when picking a CNI for a Kubernetes setup…

Again, not sure what you are talking about. I don’t care about this. It’s just that, when I need tool A and it doesn’t work on NixOS, then I have a problem. It’s not related to “perfect interoperability with traditional systems”. It’s about having something work. I don’t care if the thing needs a thousand symlinks to work on NixOS. I just want it to work on NixOS the Nix way.

Not unreasonable. You just create the impression that you feel offended about me having a problem on NixOS, although I wasn’t attacking anything or anyone, but just curious as to how things work on NixOS.

You repeatedly implied in your previous statements, that I am so attached to “traditional” systems & would like to have “perfect interoperability”, which is utterly wrong. I did never imply, that I expect this.
If I would’ve expected this, I wouldn’t even have touched NixOS.
Obviously, I touched it, because I want to use NixOS the Nix way.

Please, do not interpret stuff into my statements, which isn’t there.

It’s not about “my favourite tools”. You make it seem like, I am willing to install an innovative OS like this one, but not willing to accommodate to how it works. The whole point of me using this OS is that I use its best practices.
However, when a tool, that is absolutely necessary does not work, then no “open mind” helps.

It feels like that to you. Your feeling is wrong.

As you apparently have missed, I must emphasize, that I do not use Grub Customizer. I was just curious about the topic.

I have already said that previously.

You put a lot of words in my mouth without even reading what I actually said. That is unproductive behaviour.