It looks like this bug is intentional. I have found an old thread ( link ) where people say the same thing about previous versions of the editor. It looks like, Unity 6 is repeating the same mistakes which were made in previous versions of the editor. And this, unfortunetely, makes me stop using the editor, even though I considered it to be better then Unreal Engine editor.
I will simply quote two of the messages of that thread. If you can read, please read and think.
For the love of god, bring back the original text rendering please. Or at least add a switch.
I don’t understand why we have to deal with such bullshit.
Unusable, can’t look at blurry or oversharpen texts whole day.
Unfortunately, this is my final attempt to study Unity in the year 2024.
I hope that the editor will become better in the 7-th version.
Thank you.