Window Maker was my first window manager, but I hate to say I don’t think it has aged well.

> I hate to say I don’t think it has aged well.

Agreed.

Window Maker wanted to be the foundation of an entire "GNUstep" desktop environment, not just a window manager. Unfortunately, that environment never materialized; for better or worse, all of the development effort went towards GNOME and KDE. WMaker is still (barely) usable as an X11 WM, but there's no real ecosystem around it; based on the video at https://wmlive.sourceforge.net/, this distribution is mostly running GTK apps with a (rather ugly) theme to make them fit in.

The GNUstep Desktop Environment (GSDE) from OnFlapp:

https://onflapp.github.io/gs-desktop/index.html

This is a modern setup for Debian 9, 10 & 11.

(Not 12 yet AFAIK.)

It inherits a little bit of code from the earlier NEXTSPACE desktop, which was based on CentOS Linux:

https://github.com/trunkmaster/nextspace

NEXTSPACE is Ukrainian and development has been on hold since Russia invaded the author's country.