Auto Add Fields to Custom Report Types in salesforce

 From Winter 21 onwards we can auto-add, custom fields that you add to a Salesforce object are added automatically to all the custom report types based on that object. When you create a report from the custom report type, all the custom fields are right there for you to add to your report.

How to Enable:

Path:

From Setup, enter Reports & Dashboard Settings in the Quick Find box, and then Reports & Dashboard Settings

Enable the Auto add new custom fields to custom report type layouts

How to query all Private Reports in Salesforce

SOQL Query

SELECT Id, Name, Owner.Name FROM Report USING SCOPE allPrivate

Result