I've slowly started getting back to desktop Linux, and honestly Motif (mwm) is fine for my needs. Maybe fvwm would be slightly better.
If I where to do my career over, I'd consider going for C++ and Win32, it seems like a stable performant platform (I get that there's other problems on modern Windows).
Or a Gemini/Gopher client:
https://codeberg.org/luxferre/BFG
It just requieres TCL/TK and tcl-tls. It's run faster than compiled browsers, even if the browsers have Javascript disabled. Services:
gemini://gemi.dev News Waffle, perfect for newspapers, no ads, no 700 cookies tracking you.
gopher://magical.fish Big portal, good news service
gopher://hngopher.com HN
gopher://gopherddit.com Reddit
When it works, yes. Unfortunately, the quality of open source software, especially of big projects, has gone downhill in the later years.
Also, Xaw3D was a good effort on mimicking Motif widgets, but it had the same exact API as Xaw. And, finally, in late 90's TCL/TK had a big boost under GNU distros because it was a quick way to plug an UI over some C software.
If you like Motif, you might like EMWM too. WIth the suggest addons and extras, it's like a mini-DWM from IRIX minus the launching dock; altough you don't need it, the toolbar it's more than enough.
A pity Mosaic it's propietary; adding auth support for NNTP it's something every C novice could do under 2 minutes with a printf (and I did). But there's some nice TCL/TK software which just requires tcl-tls and a plain TCL/TK install:
It is comical in some sense that a Motif app of yore would've been a great "investment" in terms of still functioning now and for the foreseeable future.. sort of like Win32/MFC.