It’s only a partial download at first, then the rest is downloaded at the second attempt.
(the “real” test of the checksums occurs later - when all the files are fully downloaded)
It would have helped when you, in the english version of your post, start the command
pamac-manager
like this:
LANG=C pamac-manager
The output would be in english then.
copy/paste of the text would also be better than screenshots, which cannot be parsed
Why not just refresh the list of mirrors?
sudo pacman-mirrors -f
or
sudo pacman-mirrors -c Germany (or any country you like …)
or do it using the GUI …
the three dots or hamburger menu in the top row - depends on the theme you use
then see whether anything changes for the better …