Classic 360 Custoemr View case and Databricks is certainly the right platform to do so.

Strcutred Data - Stores in the Delta Tables

Email and PDFs - stored in Volumes, however, metadata as path to the volumes stored in delta table against customer-id

In order to search through the unstrctured data content (.eml or PDF), you will have to write an extraction process to extract the info such as To, From, Subject, Date, and the Body text for emails.

If you need to search through the PDF content as well (not just the names), you may want to use ai_parse_document to extract the PPDF content and store in a delta table. This steps very much depends on the how spohisiticated search you want to build.