Color scheme was kindly shared by random internet guy (I took some heavy inspiration from his setup and it is one of the reasons I tried Plasma again).
I wanted to install Plasma and see if I could make a macOS-like global menu in a futile attempt of getting more screen space in this 1366x768 display, but I couldn't make it work the way I wanted (I tried to compile Active Window Control from source so it could act like Plasma's global menu but with window controls, but it seems to be broken or I forgot some lib, I have to try again tomorrow), so it is Windows 7-like atm. Furthermore, I always see to hit the same problem with GTK apps when I move to Plasma without a clean install:
I will see if I can find the cause this time instead of nuking it from orbit (I don't have that option anymore rip), likely caused by some leftover setting I did on XFCE.
Besides that, Plasma is really solid nowadays, it is as light as XFCE/MATE on RAM, stable and has some great software (I swear KDE Connect on Plasma-Android beats even macOS-iOS integration), and way better than the "flagship Linux Desktop", AKA GNOME. I hope it gets some more traction on mainstream distros as time goes on, since Plasma 5.13 seems really promising and Plasma 5.12 was an outstanding release.