Some things updated and now my themes are all stuck like this. I use Plasma Dr46onized.
Try open kvantum manager (a GUI tool) and set the theme back to the Dr46onized one (added: Sweet-dark AFAIK). And set application style (the one in your screenshot) to kvantum.
(I use Qogir not Dr46onized but I think the process is similar.)
Thank you. That was the problem.