Yes, the vendors of the marketplace can have a separate sub-domain using the Magento 2 Marketplace vendor sub-domain extension.
The module creates URLs for each vendor’s page under the vendor’s subdomain or domain.
Now, the vendors can have their own subdomain or domain which can access by the customers directly for purchasing products.
An Example: Frontend View showing the profile page of the seller.
Please do contact us for any further queries or requirements. You can also check our Magento 2 Extensions for additional features.