Thus, when the time came, upgrading to Slackware came naturally. And I appreciated that it always was fast and lean, consuming much less resources than other distros. Now that's not so crucial, but in the early 2000's it was quite important.
Slackware was there at the right time, offering me what I needed, and it was fast and lean. And I like its simple approach to system maintenance; I can get a good grasp of the whole system.
Also, at the time Gentoo was just beginning and (again) I was using dialup Internet, paying by the minute, and I really didn't appreciate the prospect of compiling almost everything. Other distros (such as Arch) were also beginning.
Currently leaning towards Debian Testing, but that might depend on my testing of Slackware now. I use Arch daily in WSL, but I've have had enough breakages that I don't want it as my primary OS.
I would make the /boot partition twice the size the installer suggests though as on my laptop I can't upgrade the kernel because the /boot runs out of space. The laptop is used to view old manuals in PDFs while working on my car so I don't really care.
TBH any of the major Linux distros that have been around for a while are fine. I don't like Fedora or Ubuntu because they are a bit corporate.
I personally wouldn't bother with any of the derivative distros. Typically there isn't a lot different other than they've pre-configured some packages. IME that causes more headaches long term.
To me, coming from Unix, it's mostly sane.