What operating system do you use on your computer?

We live in a world where we've got multiple options to choose from when it comes to operating systems. You've got numerous flavors of Linux, each with their own quirks, pros and cons. Then of course you've got Windows, the most popular operating system and Mac OS. There's even lesser known ones like BSD (FreeBSD, OpenBSD) too! So which one do you current have installed on your computer? I have a dual booted setup, on a external SSD I have Ubuntu installed and on my internal SSD I have Windows 11 installed.