Yup. Fwiw, PieFed.social has actually defederated from hexbear.net and lemmygrad.ml, so the approach I mentioned is more for overall instances like Lemmy.ml.

Although instance blocking does very little - only muting communities from that instance, but the users can still reply to you, generating notifications when they do, and they can vote and thereby influence the visibility of your content (especially impactful when it is first starting out in a larger community and even 1-2 downvotes can prevent it from being seen by many).

PieFed, along with the Lemmy apps Sync and Connect, and the Lemmy instances lemmy.cafe and Tesseract on dubvee.org allow for true blocking of all users from lemmy.ml (the latter two requiring admin support but they have chosen to defederate from all of the big 3, and they are the only instances to have done so, thus earned quite the distinction).