Flyingrocks2736 same here! I miss notifications also! I can help you with Proton mail. Download the app, 'You Have Mail' from F Droid. Sign into your Proton account and choose at what time intervals you want it to check for mail (5 minutes, 10 minutes, etc.) After you've set it up, long press it and go to app info and turn on notifications. Now you will get notifications from Proton Mail. As for all the other apps, I have the exact same question as you. :)