Vertical Ecommerce store aggregator

What is a Vertical ecommerce store aggregator ?
An ecommerce website that connects to multiple ecommerce stores like Shopify, Amazon, Wix, WooCommerce etc.

I am building a ecommerce website to gather multiple vertical ecommerce store vendors in one location. To begin with, I am focusing for HVAC related products.

Please see my landing page
https://www.servicefolder.com/listing-apps/hvac-ecommerce.html

• We support the vendors to connect to any of the 40+ ecommerce stores like Shopify, Wix, Amazon, WooCommerce etc
• The connected store products are internally stored in our database
• Product, image, category and price data is displayed for end-users in our website

Features in the website

• Search for products - The data is pulled from our database which has multiple vendors products
• Clicking on the product will re-direct to the respective ecommerce store listing page

Benefits to Vendors:

• Another online marketing channel for vendors
• The users will directly land on the product listing page due to the marketing and SEO operations we plan for the specific vertical.
• The users can search the stores by city or do a global search. They will be taken to the vendors online store when they click the buy link on the product listing page.

Question: How do I know there is a product-market fit? Is there a value proposition to the vendors to take subscription in my website