Victor Wembanyama in 14 games has the highest playoff EPM of all time at +10.5.
Estimated plus minus is considered either the most reliable or 2nd most reliable publically available advanced stat by general managers depending on the poll. The second highest estimated plus minus is Karl Anthony Towns with a very healthy +6.8. The highest EPM playoff runs (beyond 10 games) is LeBron James in 2009 with 14 games and a +9.4, and Kawai Leonard in 2017 with 11 games and +9.4. Wemby is 14 games in (12 full games being fair) with a 10.5 (and was still 9.7 after last game, his worst in the series).
Obviously I am not suggesting that Wemby is literally having the best playoff run in history, and he could obviously underperform in the following games and this could drop heavily. I certainly would say there are still several playoff runs I would confidently put above it at this point. There’s so many factors that go into stats like these, and the sheer volume of the net swings indicates that the team is built around Wemby’s minutes to dominate, which definitely skews the stat to some extent.
But it’s not hyperbole that Wemby is having one of the greatest postseason runs since 2000 thus far, and while that could easily change for the worst, it’s still a remarkable feat 14 games in. And the box plus minus stats certainly back this up. Wemby is +50 in 4 games this conference finals while the Spurs are +4, that’s a 96 point swing (as the player playing the most minutes on the Spurs) in 4 games! He‘s won his minutes all but two games since February 1st, and all but one game where he’s played more than 50 minutes. While this could easily change and Wemby could struggle in following games, thus far his impact has been absolutely enormous. To me Wemby has an extremely reasonable case as the best player in the world right now, and has been the clear best player of the past 3-4 months and this postseason even if Jokic and SGA had better overall regular seasons.