I want to allow B2B quotes in my Magento 2.4 but I want to avoid orders, is it required custom code or I might be able to do it via admin panel only?
You won't need custom code for it, you might be able to disable your checkout via the admin panel in the configuration below.
Admin > Stores > Settings > Configuration > Sales > Checkout > Checkout Options
It will make the checkout unaccessible, the call to action to go to the checkout option disappear.
To enable the B2B capabilities, you might have the Magento B2B module installed then you can enable it, allow quotes and add your customer to a company account.