None of those.
Calendar: Google, since calendar needs to be shared and no one else outside MS seems to offer that.
Office suite: LibreOffice.
Video conference: Jitsi
Chat: Telegram
Chat, file exchange: Matrix
Email: Our local ISP's email. Our godson uses some paid email service (US based) but not Outlook or Gmail. Sister-in-law uses Proton Mail.

Avoid the Russia-based Yandex Mail.

Be sure that people know you mean, Open Talk Dot EU ( opentalk.eu ).

If you search for "Open Talk" you'll get an app (by, Jeet Productions) who is affiliated with Facebook / Meta. In fact, oddly, if you visit their website ( opentalk.club ), they don't even suggest you contact them via their app, but rather, WhatsApp (click on "Join Community, that's a WhatsApp url).

#OpenTalk

Open Talk | Buddy Talk - English Conversation App

Practice English Conversation online with Open Talk. Improve your conversational skills, make new friends, and boost your English confidence.

^{opentalk.club}

Any chance of developing bridge software to access Tuta using mail (SMTP+IMAP), contacts (CardDAV), and calendar (CalDAV) apps? (Comparative example: Proton Mail Bridge.)

Email, contacts, and calendars are all more useful when all accounts (e.g., work and personal) can be accessed in one place.