Both have plot manipulation, but the One can erase reality and so much more.
Beyond is just plot armor basically, it can't exactly fight but it will put all odds unto the user's favor.
Based on the Beyond users we know of, none of them would be able to defeat The One because they're Country/Island level at best. (Specifically Dio) Beyond would only just save them from dying somehow
The One wins, and it's not even close.
