The Show Unique Count option on the account name column will create a report showing all open opportunities and the total number of accounts represented. This option will count each account only once, even if it has multiple opportunities. The report can be grouped by account name or any other field to show more details. Reference: https://help.salesforce.com/s/articleView?id=sf.reports_builder_unique_count.htm&type=5

A roll-up summary field is a type of field that calculates values from related records and displays them on the parent record. A roll-up summary field can be used to count, sum, min, or max values from child records. You can create a roll-up summary field on an object that has a master-detail relationship with another object. In this case, you can create a roll-up summary field on Room that counts the number of Equipment records related to it. Reference: https://help.salesforce.com/s/articleView?id=sf.fields_about_roll_up_summary_fields.htm&type=5 https://help.salesforce.com/s/articleView?id=sf.fields_defining_field_types.htm&type=5

To help ensure that users who are viewing reports and dashboards are who they say they are, DR should require a high assurance session when exporting or printing reports and dashboards. A high assurance session requires users to verify their identity using multi-factor authentication before accessing sensitive data or functionality in Salesforce. Reference: https://help.salesforce.com/s/articleView?id=sf.security_high_assurance_session_level.htm&type=5