It really galls me that they removed the Motif style in Qt6, since I target that as my default look and feel. It gives a nice "This is expensive professional software with a codebase tracing back to the Reagan administration" vibe.
There are themes that come close in various attempts-- "Commonality" for Qt6/Kvantum, and some of the assets from NsCDE for GTK, but it feels like a pitched battle against design teams that desperately want to mimick whatever Apple is doing this week.
This is a KDE1 screenshot: https://diit.cz/sites/default/files/kde1-snapshot01.png
Is this really a Motif ripoff? For me it's much more like Win95 with a better titlebar in the window decoration. To each their own, but it seems quite right to me.
I can recall trying Beta 4 and probably 1.0, but at the time it felt like a weird situation. It wasn't quite everything you needed, and a lot of the apps were still obviously sort of immature. The HTML-driven file manager was interesting (ISTR OS/2 offered a similar way to customize things on a per-directory level) but it seemed like a lot of resources when a 486/80 with an obscene 32Mb of memory was my Linux machine.
Meanwhile, Plasmas Breeze (light) does all of that for me, again. One could maybe depart from the breeze window decorations, and exchange them for 'Klassy', they can 'fit', there is much to change, chose from. I'm trying them out at the moment. The thing with Breeze is, many other apps have presets for that also, like LibreOffice, which leads to even more visual consistency :-)
My desktop is blank, a mix between soft pastel yellow and 'manila' paper. No icons, widgets, clocks, weather. I don't care about CPU or Network speed there. I wouldn't see them anyway, since I tend to have windows maximized. If something would be wrong Kget or Ktorrent would make themselves known, which they won't ;-> CPU speeds suffice, even if mostly clocked down to 800Mhz :-)
My 'taskbar' is at the top, only 24px high. I switch between 3 by 3 virtual desktops by either using that too small (for that arrangement, it should grow a little when hovering the pointer over it) widget in the taskbar, or by jamming the mousepointer into one of the four corners, which makes that 'expose'-like thing appear.
StormClouds: https://store.kde.org/p/1001459
Steel (no longer shipped by default, but still available at the KDE Store): https://store.kde.org/p/1311274
As for the monitors, I have them because sometimes I have issues with CPU speed (due to a hardware quirk of my laptop) and the network connection is kinda iffy at the time.
That's different from what most laptops do, or fiddling with xgamma, or one of its frontends, using 'redshift', etc.
Even at brightest sunshine I don't go over 55% brightness, otherwise during the day, between 38% to 44%, at night just 20%, with contrast always two below these settings, or any I may use in between.
Despite all this, pictures look just right, even if I visit sites for calibration.
I see system76 is doing something similar for their PopOS?
https://store.kde.org/p/1327259 / https://github.com/pop-os/icon-theme
It uses a semi-flat design with raised 3D motifs to help give depth to icons.
I remember Noia, they were too 'shiny/glassy' and 'playful' for me. Looked different and funny for a while, but unusable for daily driving. I prefer something more 'serious', unobstrusive, not distracting.
I see someone did a Noia KDE Reloaded in 2019: https://store.kde.org/p/1293856
For shiny things, these did work for me, for a while, or could, if I retried them again:
Faenza https://store.kde.org/p/1012545 ,
Faience https://store.kde.org/p/1012543 ,
Meliae https://store.kde.org/p/1012498 ,
Delft https://store.kde.org/p/1199881 , https://www.opendesktop.org/p/1169579 ,
but I'd rather go to something like Flat Remix instead.
https://store.kde.org/p/1012430 , https://drasite.com/flat-remix ,https://github.com/daniruiz/Flat-Remix
Hedera would look good, too, if not abandoned: https://store.kde.org/p/1207800 / https://gitlab.com/sixsixfive/Hedera-icons
If they were as comprehensive & complete as Breeze I'd go for Retrofukation https://store.kde.org/p/1012499 or IndigoMagic https://store.kde.org/p/1015788 instead.
But they aren't. So Breeze it is, which is bliss...
https://slackbuilds.org/repository/15.0/desktop/fvwm95/
I like the Win95 aesthetic, but I like a close relative, KDE1, better; and I have configured my Plasma 6 setup along these lines. Screenshot: https://imgur.com/a/Q9Gfs08
Back into FVWM, Slackware also has a SlackBuild for the next-gen fvwm3. FVWM configurability could be amazing, although it can be a challenge.