I don't really think Lemmy.ml will have very good retention of new users. Because:
- New users will mostly come from reddit or mastodon.
- Most users of reddit and mastodon willing to leave are anti corporate, anti authoritarian, anti-war, pro human rights.
- A lot of posts that you see on Lemmy (either from Lemmy.ml or lemmygrad) are pro-russia, pro china or anti-western to the point of being really annoying. Its not fun to talk to people without a hint of nuance.
So it is not surprising that new users will get turned off by this and leave (or move to beehaw).