I am looking for a multivender marketplace theme

Hi I am looking at your theme first of awesome. The fact that you got one them to function so well in different areas is awesome. I am just wondering how heavy the theme is and if it will be able to support what I need. I am part of a group and we are going to open a multi vendor site. right now we have almost 10,000 members and will be uploading around 500k products. with that said. My server is 16 GB, 6 vCPUs, 320 GB SSD, 8 TB Transfer.I am using ubuntu 16.04.4. as OS. with Nginx in front of Apache. PHP-FPM furthermore I have upgraded my database from a MYSQL 5.7 to percona server 5.7 I can use 7.0 7.1 or php 7.2. I have also added 13 indexes to my WordPress tables to help optimist underlying SQL queries making database queries more efficient, while avoiding bad table scans also to woocommerce and wp themselves I have
1.Remove Pagination in place for Infinite scroll
2.Remove cast on post meta queries
3.Remove post-type category drop down
4. removed woocommerce groups
if your theme can handle it I will: Alter main query to use EXISTS rather than LEFT JOIN
I will of course be using cache and implying a small cluster for load balancing. I will use your choice of any marketplace plugin dokan, or wc vendors or any of the others what one do you feel is the lightest? my requirements for the site is a load time under or around 3 seconds max.

And I dont want to hear woocommerce cant handle those kind of numbers because it can hande those numbers because I have personaly tested a woocommerce site on a stock theme with the above handle almost 1.5 million product with a load time of around 4 seconds.So if you kniow of a theme that was built on more then paper and air to make sales and is multivendor capable plese do tell