I do like Wim Hof's breathing technique. I learned about it listening to him get interviewed by Jordan and Mikhaila Peterson years ago. It was effective. I found it helpful as a "warm up" to meditation. It is like exercising your 4 wheel drive system on your Jeep or pickup truck once a month. If you don't do that, it will get out of proper working order and when you need it to work right, it will fail you. Our bodies have these emergency mode protocols. It's like intermittent fasting, ice baths, saunas, etc. We should subject ourselves to extreme conditions occasionally and keep those protocols in proper functioning order.

In short, the guru and the charlatan will come into conflict over what the truth is. The guru could debate the charlatan but the charlatan is a charlatan so they're likely to use underhanded debate tactics like logical fallacies and gish gallups and whatnot. The guru could refuse to debate the charlatan but the charlatan would use that as a tacit admission of defeat. If they did debate, there's a reasonable chance the both sides would call one another charlatans, prideful and egotistical.

An onlooker might think both are prideful and egotistical, disagreeing with them both, and preferring his own set of ideas.

Ultimately, objective truth is objective truth, so if the guru is correct but others dismiss him as "not receptive to the ideas of others" or "prideful and egotistical" or whatever they want to say about him, that's their opinion of him and not necessarily an objectively factual assessment of him.

I think this nicely ties back to the whole "judge a tree by its fruits" thing. We won't really know until we explore.

Ultimately, if someone says they have truth to offer, you won't know whether or not they're full of shit until you've explored what they have to offer, and oftentimes, done the necessary prerequisite scholastic work/research/learning to understand that truth in any meaningful capacity.

I should point out that the first chunk of "narcissist", i.e. "narcis", and the spiritual accomplishment called "gnosis" can sound EXTREMELY similar if pronounced so. Specifically I'm thinking of an English omission of that R in narcis, i.e. "nahhcis". That same set of sounds could work for gnosis.

I find this interesting because I can imagine that many who have achieved Gnosis have been accused of being a narcissist. Likewise, many legit narcissists would falsely claim to have achieved Gnosis.