I tested debian-live-11.6.0-amd64-kde.iso and font rendering is just
perfect, both in Konsole and the whole system.
I can't find a live testing kde iso, the only ones I found were based
The Bookworm weekly and daily builds are currently on hiatus due to lack of a maintainer.
I'm downloading a nightly build of kde neon, but download speed is
awful, so no tests until tomorrow.
The only bug somewhat related I found is this one
But I'm not sure if we are talking about the same issue.
The main problem for me is I'm suffering eye strain because of all the
rainbow colors around texts, and because this does not seem to be
resolved anytime soon so I'm seriously thinking of migrating to stable
or any other distribution with more up to date packages. I can't take
this much longer.
Usually when there is a strange color issue it is due to accessibility functions being enabled mistakenly. Check to make sure you do not have blind user contrast enabled.