Shopify SEO is a template problem first
Default titles, duplicated collection copy, faceted URLs, and product schema that does not match the visible price are the usual leaks. Publishing weekly blog posts will not repair a theme that emits the same meta description on 2,000 SKUs.
A Shopify SEO audit reads the storefront: sampled product titles, collection indexation, sitemap coverage, and structured data. It is not a content calendar.