YouTube/Dom Esposito
The only way to get Apple's MacOS operating system is to buy one of Apple's own Macs. That's pretty much the way it's always been. Or at least, that's the only official way.
The computer pictured above is running MacOS, but it's not a Mac. It's a so-called Hackintosh - a computer built by a hobbyist, made to run MacOS on non-Apple hardware.
You read correctly: You don't need to buy a Mac to get the Apple experience (or official Apple apps), assuming you're willing to do the work of building one.
In a way, the reasons to buy, build, or turn your existing computer into a Hackintosh represent some of the less desirable aspects of buying a Mac from Apple - namely, that they're expensive, hard to customize, and often not exactly what you need.
Check out some of the reasons why people build their own Hackintosh computers instead of buying a Mac from Apple, including some perspectives from tech YouTubers: