Does a link in bio get me shadowbanned or hurt my reach?
The link itself doesn't. One link in your bio won't shadowban you, and there's no reach penalty for having one. That myth usually hides the real issue: if your reach dropped around the time you added a link, the cause is almost always something else you changed, like aggressive hashtags, follow and unfollow bursts, or a banned tag.
What a link can do is quietly stop working. If it's on a flagged shared domain, Instagram may strip it or mark it unsafe, so fans tap it and land nowhere. That's not a reach problem, it's a deliverability one, and it's fixed by moving to an address the platforms already trust.