It being based on one of Japan's oldest romance stories The Tale of the Bamboo Cutter, Iroha rejecting the advances of boys, Iroha fighting off boys interested in Kaguya, Kaguya openly declaring her love for Iroha multiple times, Kaguya waiting 8000 years to reunite with Iroha and Iroha dedicating a decade of her life to give Kaguya a new body seems very yuri to me.