You are not going to outrank the big players for the obvious term. Long tail phrases are where a small site actually competes, and they convert far better. How to find them free.
A good share of Google Shopping is free, and the setup work is mostly getting your website and your feed right. What Google checks, what a feed needs, and why products get disapproved.
The SEO fundamentals are not complicated: mostly things you do once, properly, when you build a site. Including why the old advice about blocking search engines in robots.txt is now wrong.
Stop pasting tracking snippets into skin templates where upgrades destroy them. One container, managed from a web interface, with purchase tracking and Consent Mode v2 built in.
Around 70 percent of baskets are abandoned. CubeCart can email those shoppers, but the feature is off by default and, before 6.7.6, could email customers who had already paid.