Help with SEO in 2021, Old dog needs new tricks.

I was hoping anyone could help me, I run two e-commerce websites, one is 8 years old, and the other just 3 weeks.

I already rank top for most of the keywords on my old website and get all the traffic I need, I used accuranker.com to track rankings and tweak, but when I signed up it was only $25/month by using a link on BHW. If I list a new product it ranks quickly without much work.

However my new store...
Are there any must-do's in today's world of SEO?
The new website is using Yoast SEO and I've already done the product onpage SEO for each keyword and optimized the site to load fast and I had moved onto looking at Accuranker again but the price is now $99 a month.

I have submitted my products with google merchant center and sitemaps in GSC, and similarly for bing. I'm just stuck to think what else must be done as it's been so long.

I've read a lot on here about blog posts, SMM's etc however I really only want organic growth so don't want to pay for fake likes. So I'm open to any suggestions please.
Thank you

You need backlinks. Just on page SEO is not enough, its just 20% of the equation. 80% rely on your backlink profile but be careful and read thoroughly on BHW about how to create backlinks for a new site as overdoing it might kill your site instead of taking off.