macOS is free. You can only run it on Apple hardware, and that’s not free. The practice of charging for OS upgrades went away about 8 or 9 years ago on Macs.
Linux is alive and well, and runs most of the internet. It’s free. But not as developed and user friendly as Windows or macOS. Because that costs money.
While Linux is free, if you want support for it, that’s anything but free. If you’re a bank say, and your website goes tits and you can’t fix it on your own, you’ll pay just about anything to have it fixed. So the support contracts for server variants of Linux are quite expensive. Same for Windows.
The upshot is you get what you pay for. Mac=expensive hardware, free OS. Windows=user friendly(ish), but costs. Linux (user variants)=free, but nowhere near as polished as the other two.
Chrome is a bit of an innovation, and that’s free. Maybe try that? You won’t get many mainstream apps for it though.
I've got an older laptop which despite having a decent enough spec was very slow, most of the HDD was filled with windows related shite, I put a version of linux on it and it's running like a dream now. If anything goes wrong on that one, well I've lost a couple of hours worth of time setting it up (mostly waiting for downloads to finish while watching TV)
Got to strongly disagree there! I've been a Windows 'power user' since 3.11, and I'm using Linux Mint for most things at home. The user experience is slick and intuitive, and a much nicer place to be than Windows 10. Lots of control, lots of (free!) useful software in the online repositories, and (so far at least) "it just works". I was expecting 'challenges' when it came to drivers for external hardware, but if anything it was less hassle than Windows.