@cassidyjames All free software usually ticks both the boxes, but beware of apps that only open-source the client and not the server (e.g. Telegram).
There are cases where the advertised "open-source" product you just downloaded cannot actually be created from its source since it has a lot of proprietary components added on top of the open core. e.g. Microsoft VS Code.
Server run by the main developers of the project It is not focused on any particular niche interest - everyone is welcome as long as you follow our code of conduct!