Operating Systems
MacOS/iOS
Much as I hate Apple for its anti-consumer behaviour, it is an operating system that's (at least marketed as being) centered around privacy.
"What's so anti-consumer about Apple, they have the best customer service in the industry?"
So long as your device is working.
Louis Rossmann will be more than happy to tell you what happens when you need an Apple device repaired.
And the best part?
Apple is just the wayfarer in restricting your ability to get your device repaired independently.
Authorized service from every company is often overpriced, because they don't attempt a chip-level repair.
They just replace the whole component, which is bad for the environment and your wallet.
Android
Android is open-source, so it must be private, right?
Okay, so there's a difference between open-source and open-core.
Android and VSCode are examples of open-core software.
They're both software which are built on an open-source core, but have proprietary layers added onto them before distribution.
This ensures that they can market themselves as being open-source, commericialize the work of unpaid volunteers, and distribute proprietary code to their users.
"But if it's open-core, why don't people just use the core and make a fully open-source version of it?"
LineageOS, GrapheneOS, and other Custom ROMs
There are a few open-source implementations of Android out there you can try.
Whether a phone is supported by a custom ROM or not is a tossup, though.
LineageOS supports a lot of devices for a lot of time, but it doesn't come with Google Play Services, rendering a lot of apps useless.
One option is to build with microg, which I have not tried and cannot give a tutorial for currently.
GrapheneOS, on the other hand, supports only Google Pixel devices (ironic, I know, but there are no privacy concerns here), has a shorter device support time (8 years for LineageOS vs 5 years for GrapheneOS), and allows sandboxed Google Play Services.
Sandboxed Google Play Services allows apps to be functional while also massively reducing the amount of device data Google has access to.
Aurora Store
Aurora Store is an alternative frontend to the Google Play Store, and it allows you to install apps from the play store without actually letting Google know you're installing them.
For the most part, it only makes sense when used in conjunction with micro-g, and not with sandboxed google play services.
F-Droid
F-droid is a repository of open-source apps for android, all of them usable on their own without any google services.
Some app developers provide their own repositories as well, such as IzzyOnDroid and FUTO.
If you want to have a phone which is completely free of google, F-Droid is your place to get all your apps.
Heck, if you want your main phone to have as few google-dependent apps as possible, F-Droid is your place.
Random shoutout
AlternativeTo has helped me find open-source alternatives to a lot of apps I couldn't do without.
Word of warning, open-source alternatives to niche apps often come with UI and UX downsides.
But as long as the functionality is present, I will take an open-source alternative (conditional on its actual maintenance of privacy) over a proprietary, cloud-based app.
Windows
Windows has managed to ruin both privacy and usability because they're just the default on so many laptops and simply don't feel the pressure to be good.
Linux
Linux has a learning curve.
You know what else has a learning curve?
Windows.
MacOS.
Everything takes time to learn how to use.
Linux Mint is a beginner-friendly distribution to use.
It is based on Ubuntu so a lot of Ubuntu's community knowledge transfers over to Linux Mint.
Steam Proton is an official compatibility for Steam, which allows a lot of games to be run on Linux.
Steam's horse in this race is their Steam Deck, their console which is essentially a Linux computer.
They found it easier to make a console out of a Linux computer and start playing whack-a-mole with compatibility, than to make a console out of a Windows computer.