I would be surprised if someone writes a custom report for you. If you really want that service I suggest you hire a local programmer.
On the other hand if you want some help in using Managers custom report writer, then you will need to read the relevant guide, make a reasonable attempt to write your custom report, then post your report definition screenshot, it’s results, and a description of what else you can’t do.
For an approach to starting custom reports see Custom Report Not Returning Transaction Type Properly - #12 by Patch
This would best be done in a different thread
Edit
Actually custom reports in the accounting program Manager, reports on accounting transactions, something which involves money. These all start with general ledger entries, but custom reports can display all linked data.
What you are describing is a database enquiry not starting at an accounting transaction. That is not possible with Manager’s custom reports. It is possible with Manager’s report transformations however they appear to be in a state of change and given the appetite for programming you have displayed, they may not be your thing.