How to design a high performant inventory report in Business Central

If we want to answer a simple question in Business Central - “How many items we have in each location?” then there aren’t that many great built in reports available. There is the standard “Items by Location” report that is not that great. It doesn’t offer exporting, doesn’t offer filtering, you can’t see item values etc. So how do we create a better report? To start designing a report the first thing we need to think about is that we need to calculate the inventory for each item in each location by summarizing the Item Ledger Entries.