Not AS observable, certainly... but observable nonetheless. Ever accurately read a person's facial expressions? Body language? Ever get a vibe as to the conditions surrounding a situation and have some of your suspicions confirmed? Those cues exist in verifiable, shared REALITY.
No, ever heard of autism.
Ever take a test? Ever come up against a problem that needed solving and you were successful? Ever witness video of animals performing various learned tasks in order to achieve some ends they desire? Unfortunately for your little game here, intelligence also is demonstrable IN REALITY.
Yean, and then what? That successful is good, is subjective. And how we treat less intelligent people also factor in to that.
A very mundane claim, and I therefore have no reason not to believe you. I will simply take you at your word on this... your word being also a thing presented IN REALITY. But do you see the reasons I am able to easily grant you this as being truer than not? Do you understand that there is nothing affecting my life or livelihood when I accept the idea that you do not value intelligence the same as I do? It is a trivial thing, and doesn't affect me. If, however, you were to tell me that your valuation of intelligence being so much "less" than my own were somehow a boon to your health, and you were telling me this so that I might adopt your same level of valuation toward intelligence, well then that would be an entirely different matter. No longer is this a simple, mundane claim. I'm going to need some evidence. Some form of justification for the belief that presents itself in our SHARED REALITY.
All fair and well, but your mental health will never be mine "one to one" or in reverse and it is not a part of a shared reality, because of differences in actually psychology.
As I already stated, your belief in God is not an insult to me. What is an insult, however, is the insistence that I am somehow intellectually, or principally failing the world or myself by NOT believing in God. And your coming to me, claiming that what I am doing is incorrect, WITHOUT THE ABILITY TO DEMONSTRATE HOW WHAT YOU ARE DOING IS MORE CORRECT, is an attack on my sensibilities/intelligence. I will always see it this way, and yes, that is my subjective experience... WHICH IS IN NO WAY ANY LESS VALID THAN YOUR OWN. Do you understand me?
There is no objectively more or less correct when it comes to this:
https://undsci.berkeley.edu/article/0_0_0/whatisscience_12
I am as correct to me as I am and incorrect to you and so in reverse.
We are playing limited cognitive, cultural, moral and psychological relativism.
I can't demand that you believe in God, nor do I have an authority to do so and I don't care if you believe or not. I can only note that you seem to think that we must be the same as how we individually cope with our individually different parts of reality, which are not shared. If they were shared, you would be me and so in reverse. So all of reality is not shared.
So here I what I learned. You believe in a different reality than me and that has nothing to do with religion or not. You believe in a shared reality I can't replicate, because you are not me and so in reverse.
So let us sum up. You apparently assume that there is a shared evidence for all aspects of mental health. That is not the case. Brains are different in a limited sense and what works positively for you could cause discomfort in me and so in reverse.