Disclaimer: I’ve only tried this with my home instance and it’s worked fine, I think I ran into issues with links from other instance, but try it out and see if it works now!
If you hold down on the app and click on “app info”, then go to “open by default”, you can select which websites should open in the jerboa app:
It’s worked perfectly for me with links from my home instance.
(This “Open by Default” feature is very useful to know about for unofficial frontends like squawker, because if it isn’t an official app this setting is how you choose it to be the default app.)
Jerboa does maintain a list of instances for you to select how to open in the app - list here and see my other comment on how to pick the instances you want.
The list can be updated with this generation script, it seems to get all the Lemmy instances with at least 50 users from fediverse.observer.