`ssty` variants are too bold

[khaledhosny]

It seems that optical size correction went a bit over the board, making them essentially bold, to the point that in super/subscript regular and both symbols are indistinguishable. $n^{n\symbfit{n}}$ gives:

Compared to Latin Modern Math:

and STIX Two Math:

[Enivex]

For comparison, here is Fira Math, which is one of the very few other sans math fonts