Hi. Content marketing to ecommerce is definitely something to care about. Just have in mind it won't bring you immediate results such as your Facebook Ads campaign.

I have experience with dropshipping businesses, and regarding the SEO content writing, you can already have great results by writing great descriptions on each product category (since it would be too laborious to have extended descriptions on each product page).

Another important thing is to have backlinks. This is the #1 Google ranking factor. Get in contact with influencers in your niche and offer them affiliate commissions or whatever it is in exchange of a product review or any mentions that point links to your website.

Just give me a call and I can guide you not only on the SEO strategies but also with the overall marketing plan.

Regards,
Carlos.