I don't think anyone, including Dr. Buhler and his team, are characterizing him as a "charismatic rebel genius". He and his teams' credentials are pretty well established and available online. There is also some history on EM propellantless propulsion, which in the past has been debunked for flawed methodology in experimentation.

The mainstream scientific community is overwhelmingly, and justifiably, skeptical. Buhler himself acknowledges the need for further study. It will clearly take rigorous, third-party research and they must verify the results repeatedly. Although it’s not impossible that Buhler’s team stumbled upon an unknown quirk of physics, it remains an extremely unlikely outcome.

Here's quite a bit more on it. The math show here is beyond me but you and RL can probably decifer it. The comments section is an interesting read too.

https://www.nextbigfuture.com/2024/04/exodus-propulsion-technologies-claims-huge-space-propulsion-breakthrough.html