I started using WindowMaker to n an old laptop that was mainly for playing music and I ended up loving it. It kinda reminds me of using an Amiga. Super fast to start, lightweight in terms of ram, and does everything I need. I like the squishy luxuries of KDE sometimes but it’s been a little over complicated since KDE 4.
Just so you know I have tried Plasma 6 and know it feels more simple, intuitive and consistent than 5. KDE has done a nice job of making it friendlier.