I was thinking just a command line tool, where you could have a config file to put your instances in. Then it would simply use the Lemmy Api and list your subscriptions for each instance. It probably wouldn’t work if you have multi factor Auth on your account though since it needs to be able to log in with just username and password. But you could make your passwords super long to increase security that way.
It would maybe be harder to keep things synchronized but depends on the api. If it’s possible to subscribe to communities from the api, it would be easy.
I’ve been wanting to make something with Go to learn it better, so this could be a nice project.