All apps have a recurring cost if the dev is continuing to develop the app. At the scale these apps are working the labor the dev puts in in the most expensive part. Plus Lemmy is continually updating so to keep the app working the dev will need to continually update.

I read somewhere that doing that makes it harder for the police to just “disappear” you

I’ve been using Connect as well and love it. All the UI customization options allowed me to make it look and feel very much like RiF. Plus the developer is very active and updates it frequently.