He is the weakest of the four of them. Really, he's about equal to the Silver Surfer. If we're talking about the original Beyonder, either he would take it or would possibly tie to Thanos.
Ummm, Korvac had the potential to reach that level. Both early stories involving the Living Tribunal saying he could grow to be more powerful and later stories with Beyonder Doom containing instead of eliminating him and his awakening being big news that would require his personal attention suggest he can be that level but wasn't ever yet that powerful.