Original article: https://www.eset.com/de/about/presse/pressemitteilungen/pressemitteilungen/security-fiasko-32-millionen-computer-in-deutschland-laufen-noch-mit-windows-10/
ESET recommends switching to Windows 11 as quickly as possible. Alternatively, a Linux distribution can also be a good option, especially for older hardware.
66.12% of Windows PCs are still on Windows 10 in Germany, 62.73% worldwide.
https://gs.statcounter.com/os-version-market-share/windows/desktop/worldwide
Windows 2000 Professional SP4, obviously.