As others have said no all-in-one solution, but Privacy Guides has good recommendations for each use case

What assurances do you have they won’t go full proton in the future?

Absolutely none. That applies to all services that exist now or in the future. The only way around that is self-hosting but that path has its own issues including a very steep learning curve if you want to be secure as well as private. Maybe this could be a longer term project to work towards?

For services:

• Mail - Mailbox.org seems the best option right now
• Calendar - don’t know.
• Drive - either Cryptomator used with literally any service or a dedicated service like Filen
• VPN - Mullvad
• Password Manager - Bitwarden
• Documents - I just use LibreOffice offline or CryptPad occasionally if I’m collabing with someone.

In truth none of these are perfect. Privacy has got a lot harder recently as Proton and StartMail/StartPage have politically shit the bed and the UK seems determined to kill encryption which means I have to avoid really good services like IceDrive just because they’re in the UK.

EDIT: Calendars. Mailbox.org’s included one works fine. You can sync using CalDAV. The process for Thunderbird (desktop) is here.

The process for mobile is a little more complicated. First you need Davx5 to actually get the data, but thats all that app does. It’s not a Calendar app. It does work with the native Android Calendar but I used FossifyCalendar.

So install both of those then login to your Mailbox account in a browser and create a Calendar (or use an existing one). Get its unique URL by looking under the heading ‘My Calendars’, clicking the three bars icon, click ‘Properties’ and you can then copy your CalDAV URL.

On your Android device open Davx5, tap the plus icon then specify ‘login with URL and username’ tap ‘continue’ then paste in the URL you copied earlier, your email address and your email account password, tap ‘login’ and that should work.

Now, switch to your Calendar app. I used Fossify Calendar so if you are too, open that up, go to Settings, scroll down to the CALDAV section and turn on CalDAV sync. It might switch to your new Mailbox calendar now, but if it doesn’t, tap ‘Manage synced calendars’ and activate it there.

Mail & Calendar -> Posteo

Drive -> Filen

VPN -> Mullvad

Password Manager -> Bitwarden

Don’t place all of your eggs in the same basket

I honestly don’t see the big deal with people hating on proton. It’s still open source it’s still encrypted and doesn’t mine your data that seams to check most of the boxes for me. The only problem I had with it was the default main client which shows upgrades to go unlimited all the time but I just use Thunderbird now.

So the whole “we encrypt your life” thing is pretty nice. But in reality look at what you’re actually doing… You have super secure encrypted email to do what? Send unencrypted emails to your friends…

It makes no sense to me… Like, you need an encrypted calendar? Why? What are you getting with encryption that you can’t get with using a VPN to connect to your local network and access a self-hosted calendar. In what was is that less secure?

Drive? Sure. VPN? Sure. Password manager? Sure. Documents? Sure. I see the value in having H/A for services like this, but all of that can be self-hosted on an rPi in your basement with a rProxy and a domain.