SEO: how to properly prepare a site for promotion in cities?

Question

Search Engine Optimization

Question for SEO specialists with experience:
There is a website, there are more than 300 cities on the website. Everything is implemented with folders like this:
my-site.ru/city/arhangelsk/products/portrets
my-site.ru/city/novosibirsk/products/portrets
, etc.
Each page of each city, for example, for the page /products/ or /portrets, has the same texts and content in the product description, in the title, in the description and in the H1 headings, but everywhere, both in the description on the pages and in the meta tags, there is the name of the city, it looks like this:
for example, page titles:
my-site.ru/city/arhangelsk/products/portrets - "Unique handmade portraits in Arkhangelsk"
my-site.ru/city/novosibirsk/products/portrets - "Unique handmade portraits in Novosibirsk"
After reading on the Internet, and looking at a bunch of similar sites that have the same content, but also diluted with city names in descriptions and meta tags, they are successfully promoted and have good traffic.
I recently introduced products by city to the site, but all my pages first got into the Yandex index, and after a day or two they were deleted, the reason is unknown to me. All the pages of each city are linked to each other, they transfer the weight, and there seem to be no "lost" pages. There are no errors in Yandex.Webmaster, I checked for SEO errors through various services - there are no particular problems, as well as in the technical part of the site.
I’m worried about this, maybe in addition to everything described, something else needs to be done, to prescribe something somewhere on these pages?
I will be glad to listen and discuss the point of view of everyone!

Answer 1

I think these pages were successful due to duplicate content, if all content differs by one city name, this is very small and it rolled until 2012, when I thus “fed” 10 million pages to Google and Yandex in the index, then search engines became smarter and you need to write texts ( description) for each city