Hello I was looking to create a new artist tag as the artist mainly goes by a different alias now and then I started having a hard time with the whole situation. There's complicating factors in that the Alias the artist mainly goes under is on their main active sfw(mostly) account, their nsfw accounts current @ is now different plus they only have emojis as their name. Their nsfw accounts @ was a slight change of their sfws alias but then they changed it to be something slightly different and now they're back to using an @ thats in reference to their sfw alias again but different as well. They go by the same artist name under their furaffinity account but they hardly use it. I was thinking instead of replacing the artists name I could tag both names so it'd sort of be like a 'Jaquin_s->Maloroid' type situation. On that note as well should any future art I could upload by Jaquin_s only go under that name since they deleted the Maloroid account?

You should use the artist alias that is most commonly associated with them across all of their galleries.
If they have deliberately separated their SFW & NSFW artworks into two different aliases/signatures, then you should keep them separate with two different artist tags.