Discussed four and a half years ago, albeit the Tweet mentions having a new source of data: https://news.ycombinator.com/item?id=10004678

The top-rated comment mentioning having an "IdentitiesOnly yes" setting in your ~/.ssh/config is still relevant if you want to have multiple SSH keys and ensure that only specific hosts get specific keys.

EDIT: Also link is to a retweet, the source tweet is https://twitter.com/FiloSottile/status/1229093553269362689