Tags don't need to have additional meta data. Their purpose is to associate content that is already organized in categories.

Got an example (or screenshot)?

I can always optimize K2 for Yandex specifically if it makes sense...

Thank you for that but I don't see anything special to add. I mean, having a separate title as you requested is simply a matter of display/preference, not a requirement by Yandex which will crawl the page either way. Am I right?

In any case, I'll have a look at their docs for any meta tags that would make sense for K2.

Otherwise, there's nothing that cannot be added using a plugin or even template overrides which append meta tags for each view.