Dark themes always make my eyes hurt after a while, no matter the colors. Those checkers are there for a reason, especially for folks with less than perfect vision.
Share what makes it clearer for your eyes. Is it less harsh than black on white. Contrast checkers miss personal factors like eye strain. They only follow set rules. Your screen brightness might change the look. Have you tested it for long coding sessions. Does it still feel good after an hour.
Ugh, those checkers are clueless! They gave my favorite theme a failing grade, but my eyes disagree after a full day. Guess my strained vision didn't get the memo.