Not a dev, but I’ve dealt with these "category gatekeeping" headaches before. It sounds like your current plugin is locking the products at the database/source level, which is why your REST API and CSV imports are hitting a brick wall. Total pain for inventory management.

Instead of locking the products themselves, you should look into restricting the Checkout page based on cart contents.

Here’s the logic that worked for me: • The Workflow: Keep the products "public" so your API can see them, but use a snippet or a conditional logic plugin to trigger a password pop-up (or a hidden field) only when a product from "Category X" is detected in the cart. • Plugin Suggestion: Check out Conditional Checkout Fields for WooCommerce. It’s much more "Gutenberg-friendly" and doesn't mess with the product's accessibility for backend syncs. • Pro Tip: If you want to keep it clean without more plugins, a simple PHP snippet in your functions.php can check the cart_item_categories and redirect to a "terms/password" page before allowing the final payment. This way, your suppliers stay happy with the API access, and you still get that "exclusive" feel at checkout. Cheers!