I am a devotee of Lord Rama and was disappointed to not find more about him. How should I interpret this?

It's wonderful that you hold sincere devotion to Lord Rama. The Sri Sai Satcharita actually provides a powerful lesson on this very topic. Chapter 19 explains the principle, "'Ye yatha mam' (As they approach me...)", which places the significance on the devotee's own actions and chosen path of devotion. In fact, the author himself shares a personal story where he decided to do continuous chanting of Rama's name. Upon waking, he found his resolve supernaturally confirmed when he heard a beautiful song being sung: "I have found the collyrium of Guru’s grace, my brother; I do not believe in anything without Rama." This shows that Sai Baba's grace supports and encourages sincere devotion to any form of God, validating your personal path.