Can you elaborate on that third condition? What do you mean by “inactive products”? Who is “him”? Do you need to check for products that haven’t gotten orders for 15 days or is that just a message to someone?
Generally, you could just use this template and change the numbers to match your use case:
https://shopify.com/admin/apps/flow/web/v2/editor/templates/6078af13-af76-49e5-aeda-c9c1ee11eea1
you would want something like “prior inventory < 10 and inventoryQuantity >= 10”.
I don’t think the “1” is necessary if you are already looking for an increase. I’m not sure why you want to cap it at 20, but you could add a third check for inventoryQuantity <= 20.