I would say read the VN (realta nua + uncensored) and then watch deen/stay night . If you enjoy the VN and like the writing play through Hollow Ataraxia. If you like Type-Moon and Nasu universe look into Tsukihime/Kagetsu Tohya/Melty Blood (VN/VN/Game or Manga), Kara no Kyoukai (movies) and Mahoutsukai no Yoru (VN NOT FULLY TRANSLATED).
Up to you if you want to watch heavens feel, but it’s a trilogy and it’ll take 1 more year to finish. The spinoffs don’t matter as long as you have an idea of how the servant/war/characters are from stay night or zero