Apple still supports the latest ones up to Tahoe, and probably security updates for a few years. You can install Windows 10 (no idea about 11) but that is only updated through next year. After that, there's Linux, of course.
macOS does get some security updates for the non-latest version, but it does not get all security updates.
https://arstechnica.com/gadgets/2021/11/psa-apple-isnt-actua...
macOS does get some security updates for the non-latest version, but it does not get all security updates.
https://arstechnica.com/gadgets/2021/11/psa-apple-isnt-actua...