It really depends on if you intend to use liability accounting (the same concept as an antique mall or a hair salon with booth rentals for the stylists) or put everything to revenue and consider the payments to the vendors as expense. The items all either link to one liability account ("owed to other" essentially) or to one revenue account for Sales. But you are right; some integrators don't provide much flexibility in their mapping. I worked with a motorcycle shop, that software only allowed service type items, not noninventory parts or other charge items, which really limited the reporting. So, service is fine and income is fine, but now your vendors' Gross sales amount (when you list it on their payments) is the grange's Cost of Goods Sold.

I avoid JE in QB.

As for individual sales per vendor: Your summary sales receipt can be per vendor name (as Customer, in that case) with their specific items listed. Or truly one Summary, and you list all the vendor-named "items" that were at that day's market. The point is to report on the items, to know the sales data, the taxable sales, total sales for fees, etc. You shouldn't need Excel; you should find all the reporting is in QBO. Are you using the Accountant Portal? It has more reporting functionality.

Did you ever get logged into the QBO forum?