Backlink Strategy for E-Commerce Website: Product Pages vs. Main Domain?

I run an e-commerce website on WordPress that sells agricultural inputs. I’ve already implemented on-page SEO by optimizing titles, descriptions, and content for my products. Now, I want to focus on backlinks to improve product rankings. Should I create backlinks for each individual product page, or is it better to focus on the main domain? Also, are backlinks necessary for this type of website, and if so, what kind of backlinks should I create? Any advice or tips would be greatly appreciated!