Do you think it would be fair to consider in asymmetric chess formats, and even symmetric ones, that the combination of a particular person, an arrangement of their pieces, and the range to their enemy could have a fair score for how formidable they are like ELO?

That is if I had an ELO in regular chess of 1500, and a very skilled player could beat me with a W/L ratio of 1:1 while down a queen and a bishop, or with fairy pieces that are weaker that their arrangement plus them also has a score of 1500 and that other 1500 combinations would also perform about 50:50? And that if some arrangement and person had a 1600 score it would win against all 1500 combinations with the expected odds?

The reason why I bring up range is because sometimes some arrangements benefit from it, or are hurt by it.

Or do you think that's not fair at all?