I installed the libksysguard-git AUR.
I can confirm that it's includes all the bug fixes I was looking for.
I was a little-bit confused, caused by the version number and 
the last updated date of the AUR (2021-02-01 23:36) is different
from the last commit's date on github.
Thank you for your kind and well detailed reply.

Kind Regards,

Dany

On Thu, 25 Mar 2021 at 03:04, Dániel Vizy <vizydani@gmail.com> wrote:
Dear Devs,

I would like to request a git version for libksysguard based on invent.kde.org 

There is a git version available: libksysguard-git ,but the package source
and the version number are different 5.21.80_r2048.gc3de4a9-1. 

Latest git version for libksysguard is 5.21.4 at the moment: 
ibksysguard/commit

I would be very appreciated for this.
Sincerely,
Dany