Yes, unfortunately, Hange met their end in the manga. It was a poignant moment for fans. The circumstances leading to their death were quite intense and had a significant impact on the story.
It's fairly common. Fans often look for more content related to their favorite shows. Since 'Attack on Titan' has a large and passionate fan base, there are a lot of fanfics available. 'Aot' fans might watch (read) these fanfics to explore different scenarios that the official story didn't cover. For example, they might want to see how a certain character would react in a different situation or what would happen if a major plot event had a different outcome.
The ending of the AOT manga was quite controversial among fans. Some were satisfied, while others felt it was rushed or left many questions unanswered.