Some impressions:
Each time I am starting Firefox, it takes 2 minutes.
Each time I am starting any LibreOffice program it takes even longer.
Starting from Thunar with a right click, adds a minute.
…
Once a program is open, it mostly works as expected. An exception is Thunar or Nautilus. Sometimes when using the back arrow it simply never returns (or takes very very long).
I am running Manjaro in a virtual machine based on VBox Version 7.0.6 r155176 (Qt5.15.2).
The disk Manjaro is running from is 4T flash drive connected via USB-3.2-Gen-2-Typ-C (10GB).
As I am also running ldme 5 in another VM without such delays, I do not believe searching the reason for slowness in the general setup would be successful.
What is the best strategy locating the cause? Please keep in mind I am a user, not a freak.
The issue itself — and the solution to it — were already mentioned on the update announcement thread itself, in the second post.
This is how we do things here at the Manjaro forum, and considering that Manjaro is a (curated) rolling-release distribution, we sincerely recommend and request that every new member of this forum would subscribe to notifications for the Stable Updates category. Every update comes with a dedicated announcement thread, of which the second post details any potential problems and how to deal with them.
Oops - sorry Aragorn - a few days ago I did a search - may be not the best one - and found nothing useful, while reading through the posts for an hour. And today it grow that stressful that I took the time for a forum entry. I should have search again.
Thank you very much, Aragorn, for the solution - it seems to do the trick.