Hi Hadi,
It's currently not permitted or encouraged to make any changes to High Contrast Black as per note 1852400 - UI Theme Designer (main note).
Creating High Contrast Themes is a specialist activity that requires deep knowledge of accessibility guidelines and is not something to be taken on lightly.
However I can see why you would want to override the logo itself.
Suggest the best option is to raise a SAP Message or putting an idea in Idea Place to ask for some way to adjust the logo.
Rgds,
Jocelyn