Hubzilla certainly has the most options for privacy. But it is ‘not perfect’. More detailed here (in German):
"Full disclosure: The encryption that hubzilla uses by default is not absolutely watertight. There are known methods to circumvent it. However, this is very time-consuming and has to be done individually for each channel. And to be clear: Other services store your messages in plain text, so we see this approach as a significant improvement for your privacy. Furthermore, you are always free to use additional encryption and password protection if you wish. To explain this in more detail:
- each channel has its own key pair
- every non-public post is automatically encrypted
- optional password protection for content via crypto javascript, browser-to-browser encryption (must be enabled in settings) Full disclosure: A malicious hub administrator could inject malicious javascript code (e.g. keylogging capabilities) into the code. Encrypt our data with GPG, become a hub administrator yourself, or use other means of communication if that bothers you.
So what is the scope of security? To put it bluntly, it may be great, but it’s not perfect."
The Channels in Friendica are similar to the “antennas” / “newspickers” in Misskey / Sharkey. Both are very good ways to receive content sorted by self-defined topics.
If you are looking for a way to *send *to different topics, Friendica’s (connected) “accounts” would be suitable for this, But Hubzilla offers more options for this
Friendica offers a connector for Tumblr as well as for Bluesky. Ad hoc I can only find a German-language manual for it: https://friendica-hilfe.gitbook.io/friendica-hilfe/basics/bluesky-tumblr-und-weitere-social-media-dienste