jointhefediverse.net seems to be a commonly linked resource for directing people to join the Fediverse.
Curiously, it does not list Lemmy under the list of Reddit alternatives. Their GitHub README explains why.
Previous relevant discussion: https://lemmy.ml/post/78808
Any way to migrate a self hosted lemmy instance to piefed?
No, it’s not geared up for that. There’s a platform called sublinks where the intention is to be initially compatible enough with Lemmy that it can be a drop-in replacement, but they haven’t released anything yet.
And with their current pace, it seems likely they never will. There’s been no major development on it for months as far as I can see.