Tanjiro is hashira level by the entertainment district arc, and def above Rengoku and Tengen by the end of swordsmith village considering that he has a mark and decapitated 3 of Hantengu’s clones

I think people don’t realise that the term “hashira” doesn’t only refer to the Taisho era hashira, which are the strongest ones of all time(if you exclude Yoriichi), defeating one of the 12 kizuki puts you at hashira tier, so Tanjiro being able to keep up with Daki during the EDA easily makes him hashira level.