I am running a Mastodon instance with 1k users. I've just found out Misskey and really loved how feature rich it is. How can I migrate my Mastodon instance to Misskey without loosing any accounts, posts, etc.?
Unfortunately, Misskey is a completely different software from Mastodon and is not compatible with databases, etc., so migration is not possible.
This is technically quite difficult, so it is highly unlikely that it will be possible in the future.