It is kind of disappointing that we cannot change the default font on Evernote macOS app, as of May 2021. It really kills the productivity as I do not like black headlines, some people are very perceptive and like colors, like myself, and I hope Evernote team adds this support soon to macOS app.
I have just signed up to write this, and this is my first post in Evernote discussions as it really is disappointing.