Kali is hard?
Kali isn't that hard as people may tell you. Let me share my story with this distro. I am not a full-time penetration tester nor do any kind of cybersecurity job but am rather a bug hunter and have used kali for more than two years having installed it many times. I also installed Debian 11 (bullseye) and Ubuntu, later on, to see what's better. "Kali is hard" is bullshit. Let me explain why
Why it isn't
First of all, kali is a Debian-based distro, so it shares many of the common features of Ubuntu and Debian distro itself.
Let's start with installation. The installation process of Debian and Kali Linux is almost the same. I couldn't find any difference between them. You have to select country, locales, keyboard map, partman, and other options. I don't remember how the Ubuntu installation process was as I installed it a quite long time ago but I think it is pretty much similar. Sometimes, kali has a problem where it can't find cdrom which was a problem of the past, maybe is still present now. Recently, I noticed in 2020 versions of installer in certain computers, it fails to find firmware which I thought to be unique to kali but it isn't.
Moving on to general features, it has pretty much the same features as any Debian-based distro. It used to have GNOME DE (which Ubuntu has) but is replaced now by XFCE which isn't by any means "harder" to work with. The user credentials are determined during setup and thus it's easy to log in. There's a panel for the terminal, web browser, and other kinds of stuff. The package manager is also the same and the one issue kali has is that some packages may not be present and sometimes cross-compatibility is an issue. Though, many general-purpose packages are available such as Libreoffice and Openbabel.
I tried adding kali /etc/sources.list to Debian bullseye and amazingly, apt commands worked well and I even installed kali packages in Debian without breaking it. You may call out the wifi issue to show kali is harder to set up but that isn't an inherent issue of kali. When I helped my friend to installed Debian 11, I found Debian /etc/sources.list has only the main but not non-free and non-contrib packages. This caused PC to not have wlsp01, and thus the sources.list has to be manually changed to include non-free and non-contrib. After some steps, the wireless interface reappeared. When talking about kali, it includes non-free and non-contrib directly from installation. In my opinion, kali is as hard as any Debian based OS. There's is nothing special about it apart from having pre-installed tools.
My guess on how it originated
So, where's the "kali is hard" issue originated from? Well, many people these days want to be called hackers, and kali is a quite famous distro so all of those Windows users probably have switched to Linux for the first time, tried to set up and install Linux, and failed. They might have asked questions that might apply for any Debian based distro, but their tag was made as if they specifically asked for kali linux. I don't have experience, statistics, or any data on how are those typical kali questions so my guesses could be wrong.
Arch vs Kali answers
Since arch is more famous as a general-purpose distro than kali, it has a wider audience thus more answers for arch. Arch was personally difficult to install for me. Also, kali isn't general-purpose OS but you could make it one by removing most of the pre-installed tools and make Debian 11 a kali like system (as I told you earlier through sources.list but may break some package? ).