Darksky, Sam, tartanpion, thanks for all your suggestions.
I have explored the url darksky proposed:
which is in fact from Sam and disabled those two services. The wifi appeared to connect instantly, but the forced log-off problem remained - to the point that I couldn’t test the wifi connection for more that 20 secs before being logged-off ( so it certainly doesn’t fix that problem).
So, the evidence seems to confirm what Sam says re: Rpi’s wifi is very weak.I’ll extend my ethernet cable and see what happens.
I also think there’s no evidence that KDE is better than Xfce, so I’ll get some more SD cards and flash another one with Xfce.
Tartanpion - could I ask you to expand on:
“I confirm @darsky’s opinion xfce without graphics acceleration or replacing it with picom is excellent, on a par with gnome under wayland only (with mutter-dynamic-buffering if necessary), with the pleasure of using all the extensions otherwise it’s not ergonomic.”
Like:
How do I prevent graphics acceleration?
I’ve never heard of ‘mutter’ - is that a gnome thing, or wayland? Can I ignore it under Xfce?
What are these extensions of which you speak?