Although what you describe is an edge case, just remove the <a> link from the author name wherever it appears in K2's templates. By the way, an extra URL is not bad with SEO or anything...

Use templating to override K2's templates so you don't lose your changes when you update K2 in the future: getk2.org/documentation/tutorials/174-templating-with-k2-and-the-concepts-of-sub-templates

As for com_content, it's not simple. It's just missing a feature which is default in K2.