Seems like raising the overall domain rating (DR/DA) of the site will boost the SERPs results. In cases like the one you're describing, Google's crawler also checks for the total number of domains endorsing your content when weighing it against your competitors' URLs. So, even if you're on an equal basis with your peers on-page SEO-wise, off-page SEO is the next essential part of the puzzle for a budding ecommerce. Nowadays, driving more organic traffic is the condition sine qua non for a budding brand, which demands opting for the all-at-once approach. Thus, aside from what you're already doing, focus on promoting your brand on socials and raising the bar with link-building as well. Such a strategy will most likely aid you in climbing the SERP ladder.