my goal is not a daily driver with this, but only something nostalgic and the idea to run a computer until it really dies and becomes totally unusable

Aight, as long as you're moderating your expectations and interested in it from that aspect. Just don't want you to spend a lot of time on it and to be disappointed -- like, no matter what the OS does, some modern graphical applications are going to have heavy RAM usage relative to what's in that machine.

anything craigslist is out of the picture, i’m european

Sure, but I can't believe that the global market for used computers is wildly different. If it were, someone would just get into the business of bulk-moving them across international lines, arbitraging them. I'm sure that Europe has analogous services.

kagis

https://old.reddit.com/r/AskEurope/comments/15tqw98/what_is_your_countrys_equivalent_of_craigslist/

There are some there.

Are those any good?

I mean, it's all relative. There are certainly people who like them enough to use them.

Fluxbox (and blackbox, and openbox) looked kind of similar the last time I was comparing them, which was a long time ago. They look and work more like a conventional Windows windowing environment. They're older and fairly lightweight.

I've used i3 myself for some time (and use sway now, which is an i3-alike for Wayland), so I don't have any criticisms of it, but it may or may not be what you want, if you're not familiar with a tiling windowing environment. It probably wouldn't be the first thing I'd recommend to someone getting their feet wet with Linux off Windows, as it's one more thing to become familiar with, and you're probably going to be doing a fair bit of that already.

I don't recall using jwm, and the last time I used icewm was so long ago that I can't recall anything about it.