I see, thanks!
It was fine two months ago, hardware did not change, only Manjaro got updates, so I can’t accept that, sorry.
SSDs shouldn’t be defragged.
You propose to replace the OS on the remote computer where nothing of software or hardware has changed, while everything worked perfectly two months ago and the only thing that changed was Manjaro and free space on the local drives.
So it is the local file system, okay, but why does a slow harddisk affect desktop redraw/program UI? If it would just take longer to show a file dialog, that’s fine, but program redraw or opening the app launcher should not be affected at all, especially since Manjaro is on a separate ssd with the usual ext4.
I will try iotop.