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However, this site is hosted on GitHub Pages, which has stated:
When a GitHub Pages site is visited, the visitor's IP address is logged and stored for security purposes, regardless of whether the visitor has signed into GitHub or not. For more information about GitHub's security practices, see GitHub Privacy Statement.[1]
I don't get a dime for advertising any of this stuff. I just like it because I'm a nerd.
Instead of iCloud or OneDrive or Google Drive, try Nextcloud. It's not perfect, but it's constantly improving and has a strong community. If you're nervous about self-hosting, check out any of these providers.
Instead of Google Docs or Microsoft Word, check out CryptPad. In addition to collaborative document editing, it also has slides, sheets, etc. Plus you get a bit of file storage for free. Collabora is a similar product that can be integrated into your Nextcloud server, but I have yet to try it.
Instead of Mac or Windows, try Ubuntu or one of its flavors: Kubuntu, Lubuntu or Xubuntu, to name a few. It's easier to install and use than ever and free to boot.
Instead of an Android or iPhone, consider a Librem 5. PinePhone is promising but is still too unstable to recommend to anyone that isn't an enthusiast for now.
If you already have an Android and want to de-Google it, try GrapheneOS or LineageOS. Full disclosure: the learning curve here can be a bit steep and there are lots of ways you can brick your device.
You might not need a "smart" phone at all. I'm happy with my "dumb" phone. The options here are limited but growing. Check out Light Phone, Mudita Pure and Sunbeam F1 for starters. Dumbphone Finder has lots more.
Go to Privacy Tools for more recommendations. And, while I can't vouch for either of them, r/privacy and r/PrivacyGuides are available for newbies with questions.