Secular Buddhism doesn't involve the supernatural or superhuman. You're conflating it with other religions. Suffering, or more accurately, dissatisfaction, is an inherent aspect of life because human beings have fundamental needs, (eg. the need for food, nutrition, water, shelter, socialization), and human beings are hardwired to seek out what meets those needs. Essentially, dissatisfaction stems from failure to meet these needs; even when needs are met momentarily, the "grass is always greener" mindset slips in and dissatisfaction occurs again. So if dissatisfaction comes from "fear of the unknown", it's because you wish something was known, and you are failing to meet that need. So if you detach from this form of striving, then your happiness will increase.
There's a substantial body of evidence supporting benefits of Buddhism cataloged in Robert Wright's ironically titled book "Why Buddhism is True."
https://www.amazon.com/Why-Buddhism-.../dp/1439195455 (
ironically titled because intellectualist truth, as philosophers have coined it, really requires attachment to concepts, and attachment incurs suffering, as we've already discussed). And of course, I wouldn't say anything about it unless I had already experimented with it and used my own mind to discern its accuracy in my own life. Neurologists have also produced evidence regarding the changes meditation incurs on the brain, such as increased density of gray-matter in the hippocampus after sustained practice of meditation. So, according to the evidence, the effects of meditation exceed a simple placebo effect.