Zoho's whole ecosystem assumes Zoho Books as the accounting layer underneath Inventory, so that pairing gets built-in treatment. QuickBooks wasn't designed with Zoho Inventory in mind either, so the gap sits entirely on the integration layer in between, not a setting either tool is quietly hiding somewhere.
This shows up constantly in practice: a business picks QuickBooks for its accounting before ever touching Zoho, then adopts Zoho Inventory later for stock and order management, and only discovers the two don't talk once they're both already in daily use.