Kann ein Native "slightly" bestätigen?

well, it is not the opposite, that would be "the same as"
but you can say

it differs "slightly" from
OR
it is only slightly different from

it differs little from is also possible, meaning KAUM
slightly = etwas (so a bit more different)

es unterscheidet sich sehr = it differs greatly
es unterscheidet sich wenig = it differs little

'Little' is theoretically possible but not what most people would ever say, as it sounds extremely formal. I would say

It differs only slightly/moderately/somewhat
It does not differ greatly/significantly