I was thinking similar, though I'm also still on X with nVidia and XFCE and am in a weird way* with programming.
I have my own custom XFWM theme that is really minimal (12px title with 8px tall buttons with some being wider to compensate, somewhat outdated example) and I'd like to expand upon it (floating titles, inset window buttons, dynamic button width, media integration) but I've looked at examples and don't understand enough to even get just a rectangle for a titlebar (though X I assume for something basic, X would probably still be the easiest).
*= the only language that I'm interested in (due to it being easy in a style I like while still having performance/capability/flexibility etc) is not popular, and worse is I have lost a bit of hope/confidence in its future (as well as its bus factor reducing further because the person who made the package manager+installer and a book walked away) so I still haven't really done much with it.