I've been one of the people saying "we don't need more users. we need quality over quantity" and i was wrong.
the way it's going, lemmy needs active users who post content sothat the network stays relevant. networks like the fediverse benefit from network effects and that means that if we have more users, that improves the value and quality of the fediverse overall.
So please, everyone, when you can, make advertisement for the fediverse in your personal area. Go talk to friends, make attractive stickers and put them everywhere, stuff like that. We would all benefit from it.
edit: source for the graph
Ask the app devs. They know how to easily set a default. There can still be an option to change the account and server deep down in a menu.
Their win is that if that modified app becomes popular it essentially still is their app and they will attract new developers and support.
I'll make a post on c/ fediverse and open source to generate ideas of how to do this this