For 32x32 you need a /16 scan panel. 32x32/8 scan is not currently supported, but may be supported in the (far) future.
I don’t have a supplier to recommend. I used to buy from Shenzhen MDS directly, but I’m not sure if they’re on Aliexpress. Nearly all suppliers have discrepancies in their listings from what’s in the title, and the specs in the listing, and the pictures shown. Be extra careful verifying the specs of the panel you’re getting.
FYI, when you buy a panel or set of panels, the manufacturer usually tries to sell you panels from the same batch of LEDs. When the LEDs are manufacturered, each batch is a little different, so the colors are subtly different. If you put two panels from separate batches together displaying the same color or content spread across the panels, you may notice a discontinuity in color between the two panels.