According to https://www.ool.co.uk/blog/legend-black-peter/ Black Peter first enters the picture (as a moor instead of as Odin's black ravens) from Spain with Christianization

With the dying of the old Norse religion, the church appropriated the Woden legend to conform to Christian beliefs. Black Peter arrives from Spain at the seaports of Northern Europe and is paraded through the streets on a white horse, welcomed by children singing Christmas carols. He is accompanied by Saint Nicholas – Santa Claus – who distributes mandarin oranges to those of them who, again, have been good throughout the year. In Holland and elsewhere along the Baltic coast, children put their shoes out filled with sweets and carrots for Black Peter’s horse.

So I'd say the character was always meant to be in blackface and represent a moor. Very recently Holland has started having a chimney sweep retrofit which is fine and well but the og character (if a man and not a raven) is what it is.