How can I limit each sub-site/store user to only a certain amount of SKUs/posts like Shopify with Ma

Since posting products are like posting posts maybe this is possible.

I have a 200,000 file limit on BlueHost, and I'm going to mimic Shopify's offerings so that each store can only post certain amount of blogs/SKUS.

How can I make this possible?

Also how can I limit how much MB/GB they can upload?