Plasma 6 also had some weird issues rendering Steam, in particular - often the window would show with the content completely corrupted (as in, a random mess of static and colors). Haven't had that issue under XFCE so far.
I have a decent desktop (Nvidia 3090, AMD 2700x, 64 GB DDR4, 2 TB NVMe) and I try Plasma every few years because I always hear positive things but my experience this time was the same as every time before:
1) It was laggy, firefox, obsidian, and the file explorer consistently take 20 - 30 seconds to start. Steam takes 1 - 2 minutes to start and lags the whole time.
2) It was buggy:
- adding and moving panels is inconsistent
- steam and other applications often fail to render properly
- the themes in the theme browser often don't work at all, or have major visual issues
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I'll probably try it again in a few years if nothing better comes along but I was really disappointed. The only issue I have with XFCE is that screen-locking doesn't work right now and I'm pretty sure that I'll be able to resolve that.
XFCE in all default configurations I've ever seen is a program. It's not part of the OS, and that's clear in the user experience. XFCE doesn't include enough control over the system, configuring your OS is a thing you have to do manually with a separate program if you're lucky. Usually it's a text file. We've all known for decades that this is why normal users think Linux is hard. KDE actually did something about it.
As much as Plasma is the best in class, it's still not good. I'd love to use anything else. I'd kill for an XFCE that works out of the box as well as plasma.
Unfortunately with the Wayland crisis, I doubt we'll see the Linux desktop brought to the standards of windows 7 anytime soon.
It's something I could do with Windows back in the day and I've always missed it