Application WEB Multi DB file management

My need is to get a multi-tenant web prototype application Use c# [login to view URL] and sql server 1 database for authentication (use of identity) Multiple databases each per company. Obviously the databases have the same structure Individual databases only need two tables: 1 "persons" table with persons (name and surname) 2 table "Attachments" contains references to some files related to the person Each company has multiple users and each user must log in, connect to the database of his company and be able to search for the personal data and view the files associated with the connected master data the problem is where to save the files (no save db) each client will have his own folder but being a single front-end are there any security problems? The alternative would be to split the front-end and-back end and create rest api which returns zipped files I accept advice