Mobile client for Android

I am slowly migrating from K9-Mail to FairEmail so I still have both.

I did set up Disroot email on FairEmail, but not on K9-Mail.

Now the Mail icon in the Disroot app opens K9-Mail instead of FairEmail. Is there a way to change this default?

AFAIK it;s hardcoded. But the question is why you go through the effort of twice as much tapping instead of going to fairemail right away.
There is literally no reason to use disroot app to launch another app that you already installed.

For example I personally (though not using android these days) use the app only for things that do not have a dedicated app. eg: privatebin (https://bin.disroot.org), forum (https://forum.disroot.org) or lufi (https://upload.disroot.org) because it makes it easier to launch (no need to open borwsr to type url etc). In app settings you can choose to disable certain apps from main window. I have disabled all apps I have dedicated app for and only left those that dont have app.

Thanks for advising.

If I’m already in the Disroot app, my email client “would have been” one tap away using the icon/launcher in the app, which at the moment seems not possible with my current setup.

If not already in the Disroot app, I certainly launch Fairemail directly as you described.