You can hide a category in WooCommerce so the users can’t see it or have access to directly.
Here are some free resources available:
Category: RFQ Checkout
How do I change the title of “”Request For Quote” at WooCommerce checkout?

Navigate to WooCommerce->settings->payments and select Quote Request
Select Quote Request:
WooCommerce Buy Now or Request A Quote – based on roles.
This post explains how to setup RFQ-ToolKit Plus to allow selected roles to be able to buy now or request a quote at WooCommerce checkout. All other customers can only request a quote at checkout.
Step1: Select RFQ and choose to show prices.
Step 2: Select to activate the rule and select roles. There are two options:
Option 1: Only selected roles can view prices. Also, only selected roles can purchase at checkout when using Option 5-buy now or request a quote. Other roles cannot view prices and can only request a quote at checkout.
Option 2: Only selected roles can request a quote when using Option 5-buy now or request a quote.
Other roles can view prices and can only purchase at checkout.
Step 3: Select option 5 to activate buy now or request a quote.
With this setup, your customers can checkout normally or request a quote at checkout.
WooCommerce Buy Now or Request A Quote (based on the items in the cart)
This post explains how to setup RFQ-ToolKit Plus to buy now or request a quote at checkout-based on type of products in the cart. If the cart contains a quote item, then customer can only request a quote at checkout. Prices for these quote items can be optionally hidden or remain visible. Items are marked as quote items in the advanced section of product setup.
Select RFQ and choose to show prices.
Step 2: Select option 5 & 5c to activate the rule.
With this setup, if the cart contains a quote item, customer can only submit the cart as a quote request.
WooCommerce Buy Now or Request A Quote
This post explains how to setup RFQ-ToolKit Plus to allow customers to buy now or request a quote at WooCommerce checkout. Customers can purchase normally at checkout or request a quote. You can optionally put a minimum purchase requirement as a condition to request a quote.
Step1: Select RFQ and choose to show prices.
Step 2: Select option 5 to activate the rule. You can optionally put a minimum amount to be eligible for asking for a quote. Below that amount is only option to purchase.
With this setup, your customers can checkout normally or request a quote at WooCommerce checkout.