Currently, we are not able to capture calculated fields through Salesforce connector. In a separated ticket, we have the confirmation from engineering team that this is a product gap, as Salesforce Commerce Cloud doesn't support syncing custom fields. 
 
We would need c_geOrderNumber which is a custom field.
 
We were also told that Fivetran team is working on implementing the feature to support custom fields, but the project might take some time to complete. The estimated date of completion is October end, 2023.

Please update us if it is available.

Many Thanks