I have some MX Browns in a KUL that are VERY scratchy, but in a Varmilo I have MX Browns that are much smoother. I wonder why and I wonder which of those are closest in the scratchiness with the newer MX Blacks you have.
It's just a crappy batch.
In my first mech browns was extremely scratchy, to the point were any "break in" can't possibly helps. In my current board on reds about 90% of switches is smooth (and a lot of people describe reds as awfully scratchy).
So, in such MX inconsistency from batch to batch any opinion is futile. Buying keyboard on mx is the same thing like rolling the dice.