FAQ/knowledgebase are not enough to reach 95%. If that was the case then this problem would've been solved long ago with the advent of semantic search engines.

You also need the following:

1) General principles of instructions split across topics - essentially distilling a support training manual into a flow chart of prompts.

2) Algorithms to detect best past resolutions to create new knowledge-base material on the go.

3) Continuous retrain and feedback loops which we have written models to perform on behalf of customers.

And continuous R&D effort into how these systems can improve.