What I am missing?

You're better off optimizing for Amazon A9 search pages than Google SEO SERPs

As @obswain says, you should concentrate on ‘ranking’ on amazon not google. If you’ve got the cash invest in an initial boost of amazon ads - for a few days - after which you should get sales and start to rank naturally (as you probably know sales/conversion rates are the important things for amazon ranking).

Hey guys,

just one thing what would be consider branding link on amazon product page:

"ProductBrandName" or "amazon" or "ProductBrandName amazon"

So, I also build branding links not only URL links

Thanks!