You could try the “LocalDocs” feature of GPT4ALL.

Well, now it can

No, Mull browser has nothing to do with Mullvad VPN.

It keeps asking me to allow it to connect to the internet. What for?

Easy install, OTA updates, you can buy a Fairphone preinstalled with it.

So mainly easier access I would say, while not having a downside.

For mobile I also recommend Finamp. It is FOSS and built for Jellyfin, with offline support.

I am using the beta which has more clean UI and is very stable.

I there a way to install multiple languages? I, for example, would like to install both English and German so that I can switch between them depending on the language of the text.

Is there a way to install multiple languages? I am would be using German and English, sometimes Italian.