Windows Vista. I absolutely decked it out with free/open source software (LibreOffice, Firefox, Thunderbird, KDE for Windows) before I dual booted Windows and eventually made a more permanent switch. Never looked back.
I did have to use Windows for my old job (Win10 from memory?) but now I have a job where I can use Linux.
Next step is to switch my partner over from Windows 11 (she’s already on board with the idea).
The main reason I’ve steered clear of OpenSUSE is its commercial backing as opposed to being a true non-profit community distro like Debian or Arch.
Red Hat have influenced Fedora decisions before and obviously blew up CentOS as a RHEL clone when they had the chance. Canonical constantly make bad decisions with Ubuntu.
I will add that I’ve heard nothing but good things about SUSE and OpenSUSE. SLES sounds like a decent alternative to RHEL and the OpenSUSE community distros sound pretty solid.