Is it worth building a custom Libre fork for internal use when working in a closed network?

[eranpenso]

I work in a closed/offline network where I manage my own RAG (retrieval-augmented generation) services (self hosting llm, vector db, search api). Because of the restrictions, I can’t use any outside APIs, SSO, or external authentication services.
I’m considering developing a custom app based on Libre or a Libre fork that’s tailored to our internal environment and security requirements.
My main questions:
Has anyone here worked on building custom Libre forks for specific internal needs?
Is it worth the investment to go that route (maintenance, updates, etc.)?
Would you recommend building from scratch instead of forking Libre?
I’d really appreciate hearing from anyone with experience in this area — especially about the trade-offs between flexibility, cost, and long-term support.