Customer specific docs

For flexible B2B tools/platforms where customers can do different configurations, setups and use the tool in different ways, I have observed that companies create customer specific documentation.

Users also create onboarding guides, help articles and documentation for their internal usage. I have observed this usually happens within their internal knowledge bases.

I am wondering if there is a need for a documentation portal with customer specifc sections. In this way, the best practices and the confidential info can be shared instead of emails, gdocs, notion and PDFs where this info currently resides.

Would love to know if you have all seen any instances of this, if you think this would be useful, existing tools where this already exists