> buster, my laptop has "become slow" by which I mean applications take > longer to open, new windows take several seconds to complete drawing on > the desktop and there's a noticeable lag when I use the mouse to select > text (you can see the text becoming highlighted one char at a time).
Reminds me of things I saw when using Gnome on a system where there was no driver for the GPU (aka "3D graphics"). Maybe it's just some firmware missing or an old /etc/X11/xorg.conf forcing the use of a now-discontinued driver? Just a stab in the dark, sorry: my crystal ball is still sleeping, Stefan