Ahah, seeing the title, I thought "huh... Linux?".
But yeah. A more direct "alternative". ReactOS is now a very old project, and has never really took off. It's what? 20 years old or so? And still never reached anywhere close to version 1.0...
It's of course a lot of work, and was an interesting initiative at the time. But I honestly don't think it will ever be useful.
If you need to run Windows apps, your best and most robust bet these days would just be Linux + Wine. Now if this combo is not fit for your purpose for performance reasons, or hardware support reasons, I really doubt ReactOS would be close to giving you a better alternative at this point. So...
I'm admirative that some people are still working on ReactOS, though. Given the state of things, it could have been abandoned entirely.