At what point has the artist said they're 'fixing' Touhou? Unless proven otherwise, that reads like you putting words in their mouth.
exactly, it's literally just an artists personal rendition of touhou characters. By no means is this canon, it's the artists choice how they draw certain characters and it doesn't have to line up with the "canon" design. these were made because of the blacktober trend last year where artists would draw black renditions of characters each day, it is by no means an attempt to "blackwash" or "fix" any series since it's just drawing a character in a specific way, and this way happens to be with dark skin.