The manager goes to the people, who really know how to make a report (maybe that is "accounting"?) and asks them to make the report taking into account some single report specific things that they talk about. Then those people, who know how to do it deliver. They might have someone in their team, who knows how to work with dataframes, which would come in handy. Those people store the program written to generate the report from the data and are ready to modify when more is requested. Instead of doing code in Excel, they simply write their code in whatever language they use to process spreadsheets or other data sources.
If they have knowledgeable people there, it will take no longer than coding something up in Excel and will be more reliable.
I guess no one has used Power BI for reporting... Link the data source, save the view that "Manager A" wants every week or month, setup on premesis gateway, and your new reports are there before your are asked for them again. Always up to date. Then share your dashboard.
Also, you guys should be ashamed of yourselves. "not sure who does the reports, maybe finance?" Eceryone should know how to make their own reports.
If they have knowledgeable people there, it will take no longer than coding something up in Excel and will be more reliable.