Does one subdomain influence the rankings of others?

Question

Search Engine Optimization

Actually, this is the situation: one of the subdomains of the site has quality problems, will it have a significant impact on the ranking of the main domain and other subdomains in Google and Yandex? Have there been any experiments on this?

Answer 1

there was a sad experience, the 3rd level domain was indexed, the subject was significantly different from the main domain, as a result, the loss of positions. Google is very long and reluctant to part with deleted pages.

Answer 2

domains don't matter,
only URIs and links between them matter