To answer this question succinctly, Hashira are indeed allowed to date. In fact, a number of the Hashira are in happy relationships already. The Sound Hashira Tengen Uzui has three wives that anime-only fans will meet when season 2 of Demon Slayer debuts later in 2021. Furthermore, the Love Hashira Mitsuri Kanroji is in an ongoing relationship with another member of the Hashira!
I'm running out of prompts, so comment anything you want to see later on! <3 Tanjiro You and Tanjiro sparred every now and then. You had watched him fight, and his sheer power along with the durability of his skull amazed you. You knew, however, that he held back when fighting you. Whether it was to spare your feelings or he was afraid of hurting you, you didn't care.