Why would anyone ever believe either of them would actually go through with it? It's a free PR stunt to stay relevant and also an ego boost for them. Leave it. Act like it doesn't exist. It's trash and should be left in the dumpster, along with those two.
Zuck at least trains BJJ, which is by far the most cardio intensive workouts I’ve ever personally done (and I grew up playing several sports competitively). I don’t think he’d gas, but I don’t think he’d be looking to beat Elon down either. He’d probably just grapple him and submit him quickly since Elon is both unathletic and has zero knowledge of how to roll.