I think search is the wrong lens to look at it. Yes, finding relevant information quickly is important, but the key to enterprise search tools would be to get a holistic view around any topic. A typical enterprise has a lot of silos (12 out of top 15 enterprise apps on G2 are addressing this problem) and the flow of information doesn't exist. Any enterprise search tool helps in aggregation and triangulation of conversations/knowledge from various sources, helping any user get the sense of 1/ what is the current state of this topic? 2/ how did they get to this state? (you would have guessed it, you need a knowledge graph for the product to work well)

(Disclaimer: we started with enterprise search too, and now we think a custom model is a better way to get to those goals) Also, the output needs to be integrated into their own workflows. Eg: Seeing a conversation on slack and using a bot fetch all the supplemental information to understand the context from say mail, docs etc. is mighty useful. Search using RAG is the easy part, the hard part is contextualizing it in a way it is immediately useful. That depends on understanding the company/domain lingo, understanding users, etc.

Private aspect is a bad UX but not a bottleneck. Remember, this is targeted towards power users looking to use it on a daily basis. Connecting the bot once to get started is fine as long as it adds value. If anyone offers data governance along with it (updating access on a daily basis and answers only from access), it could be a huge hit.