If you tell someone that fedi instances are like email providers and that your instance is transfem.social, that creates three expecations in your audience:

1)The main, or possibly only, way to access your fedi account on a desktop is through the transfem.social website.

2)The main, or possibly only, way to access your fedi account on a smartphone is through the transfem.social app. This app is completely separate from the apps that could be used to access a fedi account on another instance.

3)The primary difference between transfem.social and other fedi instances is the UI of the website and app.

Frankly, I don’t think this is that big of a deal. First introduce them to an instance, then once they figure that out, show them the apps and other ways to access that instance.