You got great choices, actually. I'd only recommend to be as little dependent on multiple fronts on one company. So I'd change a few of Proton to something else. As long as Proton doesn't replace their CEO with an explicitly antifascist one, I don't know if they re a good spot.

Depending on how private communications must be, Threema might be better than Signal.

If you don't need to synchronise with others and your threat model is not physical attacks/theft, then agendas can be just on paper. Same for the calendar.

As for distro...

Mint is great (and honestly what I'd rec for people brand new to Linux). If you want to harden privacy/security more though, the following Linux distros might be better:

• Fedora (any of them). It's an international upstream distro from Red Hat (American company, parent company is IBM). In other words, it's developed by the community, which is gathered in the Fedora Project. Their headquarters is in NC, USA. Red Hat then uses the community distro to make their own distro, and in return, finances Fedora. Linus Torvalds, the creator of Linux, uses it. If he trusts it, I trust it.
• OpenSUSE Tumbleweed -, developed by the OpenSUSE community, backed by OpenSUSE from Germany. Pretty good all-arounder.
• Arch Linux, developed internationally, but most devs are spread across Europe. Has an extensive wiki (that also is good for other distros), though it's not exactly "plug and play" and I'd rec it only if you know what you're doing.
• Debian is another option if privacy is less of a concern for you, than it being FOSS. It's one of the most FOSS distros out there, and also highly independent and international.

I assume you want to use your distro as daily driver, and that your threat model isn't too severe. So the above ones should suffice.

If the threat model calls for it, or you're willing to sacrifice some usability for slightly more security, you could try QubesOS (arguably one of the most secure distros since it sandboxes everything as if they were a separate computer). Tails is another alternative, that's on a USB and forgets itself after usage.

For search engines...

... go for Qwant (French) or Ecosia (German). Both are European-owned and are busy constructing their own indexes (currently they still use Bing and Google). There's Mojeek (UK-based) which is independent.

I don't know how to block specific sites from popping up on them though, since I notice a certain trillionnaire's personal ""wiki"" pops up a LOT. Probably he's cheating and search bumping to spread his desinformation. It should be blocked.

Presearch also exists, which is decentralised and uses its own indexes. If you want OSS, there's SearXNG and YaCy which have metasearch options. Be careful in which instance you pick, though.