The default GUI is really a low contrast and washed out version compared to the old one.
I noticed, that there are chances in the settings to change colors, but not all. 2013 Windows style looked like this.
Check the latest MS Office Outlook ribbon - no longer low contrast - crisp and clean symbols and high contrast. I don’t think people who write, want to see grey text on light grey backgrounds.
Please, make the default a high contrast and then some people, who may have sensitive eyes, can change the theme to more bland. This is supposed to be a functional tool - and I don’t feel it is if you have hard time reading the text!