Is it possible to limit the commission rate for specific products?

It is not possible to select specific products to apply the specific commission rate of a campaign/

The commission you set in the campaign detail is applied to all products on the site.

You can edit the affiliate promote link to make it become a product link or collection.

For example https://booking-nga.myshopify.com/collections/all?ta_aff=YWVSCUSWIZ => https://booking-nga.myshopify.com/products/3-4-sleeve-kimono-dress-coral?ta_aff=YWVSCUSWIZ

Get the poduct link here (affiliate dashboard)