I think a lot of confusion about the fediverse stems from the fact that most services default to your local instance as front page. I know you can change it in the settings here, but the setting is also defaulted to local, so maybe that one should be set to all, too?
This is actually tied to whatever you select at the time of account creation for Lemmy in general, not just a Jerboa setting as far as I can tell. It's likely a different way of defining such a behavior than we're normally used to, but it works well, I think. That said, I think this is more of a Lemmy suggestion than a Jerboa one.
You don't need a new account, just that's what lemmy does by default. You can change it in the settings to show all communities. However, if it were to default it to all, it might be less confusing to the masses.
I'm sorry, I was super unclear, you can change this setting at any time in your Settings page and it should stick. If it's not sticking, it might be something with lemmy.ml