This is not an uncalculated risk.
This is not a risk he hasn’t taken without doing training to accomplish the task.
Lots of Christians take serious risks all the time. Firefighters going into burning buildings, not even sure there may be someone in there alive to save. Rescue, police.
Just standing on the side of the freeway talking to a motorist, can get a cop killed.
People work around dangerous machines that could kill them. In earlier times they didn’t have emergency shutoffs, or any kind of guards around gears and belts that could grab clothing or hair and pull you into a machine and kill you, and they were Christians. Taking risks.
He’s not doing it without training.
If he was just a normal person who just woke up and said he was going to do this, no training and no preparation, no tests on other easier less dangerous things, but said he’d do it just because he’s a Christian, then yes, I’d agree with your assessment.
It’s not the level of risk I find appalling—as in every one of your examples, men are taking risks for the sake of the safety or very lives of other people. Those are all acts of love and sacrifice for the sake of others. Wallenda is doing so for measly entertainment.
Whether he gives all praise to Jesus, and has lots of training, is beside the point—what he’s doing is foolish. Risking your very life just to give yourself or others thrills is not right.
As Dave W said above, he has the status of a snake handler. Yes pray for his safety, and his wisdom to quit taking wholly unnecessary—utterly foolish—risks.