Quality after edit and cleanse

[M5E96]

Hello,

I use Adobe Acrobat Pro DC (+ Windows 11) to modify documents and drawings. If I save the document after editing or after disinfection, the quality decreases considerably. What am I doing wrong??

Below you can see an example.
Picture is the original document.
The second picture shows the document that has been edited/disinfected. The quality is visibly less here (see the tightness of the letters).
The third image shows what happens when I want to edit the redacted document. Some letters are not even recognized and displayed as strange characters. (for example '911', you can edit this in the original document).

[M5E96]

Is there nobody who can help me?? 😞