One possible theme could be the fear of the unknown. Since it's a horror story, the 'bhuter' (if it's a supernatural entity) represents something that people don't fully understand.
The 'bhuter golpo horror story' is a bit of a mystery to me. However, generally in horror stories, there are often themes like fear of the supernatural. If 'bhuter' represents some sort of supernatural being, the story could be about how people in the story interact with it, perhaps being haunted or chased by it. It could also include elements of mystery, where the characters are trying to figure out how to get rid of the 'bhuter' or solve the mystery behind it.
There are numerous interesting Hindi movie stories related to Bollywood actresses. For example, the story of Priyanka Chopra's journey in Bollywood is quite inspiring. She started as a beauty pageant winner and then made her mark in Bollywood with diverse roles. Another one could be the story of Deepika Padukone. Her entry into Bollywood was much talked about, and she has since starred in many blockbuster movies, each with its own unique plot and her character's journey within the story.
The Bhoomi Hindi movie does have a basis in true events. However, it also incorporates fictional aspects to make it more engaging and cinematic. But the core inspiration comes from real-life circumstances.