Can SEO sanctions be applied for a large number of subdomains?

Question

Google

Now there are regional subdomains, without addresses, the content is the same, only the name of the city on the pages changes. There are also location subdomains in Moscow and several cities in the Moscow region - they work on the same principle. While everything is normal. There is traffic for commercial requests.
It is planned to increase the number of locations. There may be a couple more projects on subdomains. But most of all, cities will be added - more than 400.
I am afraid that with an increase in the number of subdomains, the entire project may lose credibility, fall under some kind of filter that reduces the effectiveness of pages, and a drop in search positions.
Is there a similar experience? Can you share your thoughts?

Answer 1

It doesn't matter if you have 400 or 10 subdomains. If your site has been around for a long time, at least for several months, and everything is in order with the positions on all domains, then adding new ones will not change the situation. But my advice is to do the maximum uniqueization between subdomains - sooner or later search engines will impose sanctions for this, since the manipulation of the issuance is in fact.