To achieve the desired filtering in Salesforce report based on Loan and Loan Team Member Role object, you can use a combination of filter criteria and a cross filter.
First, add a filter criteria for the Loan Team Member Role object to exclude all Loan Team Members with a role of 'Loan Specialist'. This will exclude all Loans where there is at least one Loan Team Member with a role of 'Loan Specialist'.
Secondly, add a cross filter to exclude all Loans where at least one Loan Team Member has a role of 'Loan Specialist'. This will exclude all Loans where there is at least one Loan Team Member with a role of 'Loan Specialist', regardless of the roles of other Loan Team Members.

1. Open the report in the report builder.
2. Click on the 'Add' button in the 'Filters' section of the report builder.
3. Select 'Loan Team Member Role' from the list of available objects.
4. Select 'Role' from the list of available fields.
5. Select 'not equal to' from the list of available operators.
6. Enter 'Loan Specialist' in the 'Value' field.
7. Click 'OK' to save the filter criteria.
8. Click on the 'Add' button in the 'Cross Filters' section of the report builder.
9. Select 'Loan Team Members' from the list of available objects.
10. Select 'Role' from the list of available fields.
11. Select 'equals' from the list of available operators.
12. Enter 'Loan Specialist' in the 'Value' field.
13. Check the 'Exclude' checkbox to exclude all Loans where at least one Loan Team Member has a role of 'Loan Specialist'.
14. Click 'OK' to save the cross filter.
15. Once you have added these filter criteria and cross filter, the report will only show Loans where none of the Loan Team Members have a role of 'Loan Specialist'.