haha it's very much a work in progress! To clarify, the Lemmy functionality is only partially bridged.
What
that means is, the first step of pulling in posts based on topics uses
the Lemmy API directly, and it's only when clicking on a post to be
directed to that Lemmy community when the bridging occurs.


That bridging of Lemmy community into a Nostr profile is done primarily using @alex
's awesome Mostr.pub Nostr <=> Fediverse bridge. While it doesn't
fully support Lemmy yet (more Mastodon focused), it works decently
well! As a fallback, I use RSSLay to generate a nostr profile from the
rss feed of that Lemmy community.

For Bluesky,
I'm running an instance of Bluestream, which generates RSS feeds for
Bluesky profiles, and then using RSSlay to generate Nostr profiles from
those RSS feeds.
https://gitlab.com/soapbox-pub/mostr
https://github.com/kawarimidoll/bluestream