Combine workbooks or connect them to work together?

Hello Everyone!
I am looking for some general advice rather than anything specific. If needed for clarity, I can later send more data.
I have 2 separate workbooks; Warehouse Inventory and Warehouse Suppliers.
Warehouse Suppliers has multiple sheets(4) with each sheet containing a particular vendor's product data and pricing. Using Power Query, I merge these sheets into one Master Vendor table. All works great.

WB Warehouse Inventory also uses Power Query to combine 4 city warehouse inventories into one Master Inventory list for the entire organization. All works great.

My dilemma: The WB Warehouse Inventory needs to look up product data from WB Warehouse Suppliers.
Should I move all of the worksheets from Warehouse Suppliers into Warehouse Inventory?
Or, should I leave the WBs separate, and have Warehouse Inventory link to Warehouse Suppliers?

Do I need to setup a Data Model for either of these options? I have had bad luck with Data Models in the past. Looking for the easiest options, both for myself and for my client.

Thanks so much!