Syncthing. Works really good for paying nothing.

Edmund said there’s will be a normal online coop, finally.

Or create your own Zettelkasten using Logseq or Obsidian, it’s a very cool thing.

Lemmy.ml is in Swiss?

The most secure app I know is SimpleX. It is like Matrix but without an identifier, so you really interacting only with people you want. No one can reach you unless you gave him a link to connect to you.

Two different people cannot be ensured they are talking to the same person since there is no identifier they can compare to.