Seller Onboarding WordPress WooCommerce Site

We are an E commerce site;

Previously we introduced seller segment with the help of a paid plugin

"Multivendor Marketplace Solution for WooCommerce - WC Marketplace"

it had all features we required Like

seller onboarding / verification
seller dashboard
automated order processing
single and bulk product
seller profile management
seller revenue management

But issue we were facing was - it slow down the checkout processing more then 60 sec

now we are expecting Standalone site for seller onboarding integrated with main site

with the help of same plugin or share if any other solution available