In Magento2 Marketplace, sellers can manage the tax rules which can only be created by the admin.
After this, the seller can select the tax rule for the product while adding/ editing the product. In the Marketplace configuration, there is an option to select if the tax amount will be calculated under seller amount or admin amount.
If you want the option to sellers so that they can create their own tax rule then it can be achieved by installing the Marketplace add-on Magento2 Seller Marketplace Tax Manager.
Under this add-on, Magento2 marketplace sellers can manage the tax from their end. Using this module sellers can add new tax rates, tax classes, and tax rules. The store owner can also find the Tax rates and Tax details of each seller.
If required you can also check our live demo as well from the module link.