I think Red Widow is either a revived Yelena Belova or a clone of her. Yelena goes by the codename Crimson Widow on the Avengers cartoon. Also didn't the Red Room make several clones of Yelena?
https://marvel.fandom.com/wiki/Yelen...28Earth-616%29
https://avengersassemble.fandom.com/wiki/Crimson_Widow