How to disable shipping to parcel lockers for certain products?
Option 1: Weight limit
If you're not using the weight attribute in Shopify, you can assign a weight to selected products (i.e. 1 kg) and then set the weight limit option in the InPost Lockers app to the same weight (i.e. 1 kg). The existence of such a product in your cart will cause the parcel locker delivery option to not appear.
Option 2: Tag exclusion
You can assign a tag to products, for example, "large-product", and then in the InPost Lockers app, check the "Enable product exclusions" option and enter this tag. Shipment to parcel machines will not be available if any of the products in the cart contain this tag.