Debian uses systemd as its default init system
Devuan was created specifically to avoid systemd, offering alternatives like SysV init, OpenRC, and runit
I do not know what an init system is. I don’t know what systemd is. I do not know what Devuan is. I do not know what SysV init is. I do not know what OpenRC is. I do not know what runit is.
I vaguely understand what debian is. Although I would be the wrong person it explain it. I know it’s the type of linux that ubuntu is. And I know it seems like every disto I look at says it’s based on ubuntu, and therefore is debian since ubuntu is based on debian.
What I don’t understand is if everyone hates ubuntu, but ubuntu is based on debian, but nobody hates debian, why is everything based on ubuntu and not debian?
How do I know if I want the debian version of a distro, or the devuan version? What are they even talking about?
Debian makes the deliberate choice to have older versions of software in the repository so that there is plenty of time to become aware of and fix any problems that come up. This is a reasonable stance to take, but in practice often newer software is stable enough, so Ubuntu essentially starts with Debian as a base and then adds newer version of software into the repository. This approach made it very popular, and as a result it effectively became a standard (in addition to RedHat/Fedora), which is significant because it means that a lot of software is now packaged to work best with Ubuntu. Both of these factors motivate many distributions to base themselves on Ubuntu. Unfortunately, Ubuntu also adds in a lot of stuff that… people disagree with, but the good news is that a distribution is just a collection of software, so there is nothing stopping someone from picking all of the parts of Ubuntu that they like, and leaving out all of the parts that they don’t.
An init system is essentially infrastructure that runs underneath the hood to orchestrate what things get activated and when. Some people (not myself) consider systemd to be overly complicated so they prefer something that they consider to be simpler, and others oppose systemd on essentially ideological grounds for not being sufficiently “Unix-like”. If you do not understand enough about init systems to understand the difference between these systems and their pros and cons, then I would highly recommend that you not care at all about what your init system is (outside of curiosity for its own sake), and be a little suspicious of distributions for which their init system is their main selling point compared to other distributions, because it probably means that they focus their time and energy on things that you have do not care about in practice. (Having said that, don’t get me wrong: the great thing about Linux is that if someone really cares about this kind of thing, then they are completely free to tinker to their heart’s content until it is exactly the way that they want it!)