My latest experience with seo

I just want to share my experience, I'm a professional but I wouldn't call me an expert, I started my journey being a student and made some websites that kind of worked and was the reason I started getting jobs as a seo, I have learned a lot since then because I've been able a lot of expensive tools that I couldn't afford and I'm getting good results for the company I work for. Since all that happen I decided to start my own projects in my spare time and right now I'm working in a dropshipping with my girlfriend and in a blog that I'm going to transform into an affiliate website in the future.
The funny thing about it is that I'm perfectly optimizing the blog, images, videos, kw density, interlinking, I looked for a not so competitive niche, etc; and the drop shipping that I'm making with my girl that is barely optimized just has a kw research for the product titles, but it stills has some names from aliexpress due to oberlo importing products, and it's in a super competitive niche is getting 10 times more traffic than the other.
I can image some mistakes that I'm making and also the fact that 2 people are working in it has more ideas for the content and ux. Anyways, this only teaches me that I still have a lot learn about seo and that optimizing isn't everything.

Hope you guys can learn from my experience, share your stories, teach me something or just enjoy my horrible English.

TLDR: the messy website that I'm making with my girlfriend has 10 more traffic that the website "over optimized" That I'm making by myself.