If your PC is in another language, that shortcut gets changed. For example, in spanish it’s Ctrl+G (G from Guardar, I assume). It may seem intuitive, but not every app follows this change. It’s also way more difficult to hit with one hand, as the G is further from Ctrl than the S. Localized shortcuts are a thing I never understood about Windows, and I hated it while I used it.
After that I swithed to Linux, and I’ve been using NeoVim for a few years now. Instead of Ctrl+S I now compulsively [esc]:w[return], which, now that I think of it, may be even worse.