When I was a young child, I naïvely believed anything I experienced or that anyone told me as true. As I started adolescence, I started to question that, and realised that people who tell me stuff might be mistaken, or intentionally lying to me. I became very interested in optical illusions, and realised my senses could be fooled too. I had to rely on measurable, repeatable truth that scientific experts had written in pop science books.
Then I thought about simulations, being in a story (like in Sophie's World), gods, and every other possibility that the entire world I experience is not real and is created to test me, to observe me, indifferent to me and I'm there by accident - whichever it was, I couldn't believe for sure that anyone besides me really existed, or anything I knew through my senses. Only my logical reasoning could be trusted. I am doubting therefore I exist, but I couldn't know anything else for sure.
Until recently, I realised when I was ruminating one time, and thinking about which is better: truth or happiness. Most of the times I'd ruminated, I knew I'd come to the conclusion that I'd rather be right than happy. I had logic to back this up, it's more important to know the truth because then I'm happy about being right. But when I'd been happier, I thought being happy was more important than being right - after all, what's the point of being right if it doesn't bring you pleasure, seeking pleasure and avoiding suffering being the whole goal of life?
I realised that what I thought was logical reasoning to support my conclusion wasn't logical at all. It was a rationalisation to support whichever conclusion made me happier at the time. When, for chemical reasons in my brain, I was happy, I wanted to remain happy. So I'd subconsciously convinced myself that I had logic to convince myself that happiness is preferable. When my hormone levels were low so I was feeling down, telling myself that at least I feel better because I know the truth is a way of coping.
And I realised that when my 'logical' reasoning is just a rationalisation for an emotional state caused by brain chemicals and my body, I can't trust any 'logical' argument my brain thinks of. I don't exist because I'm thinking, I exist because I have an innate sense of existing. So therefore, I can't trust anything I think is logical. But wait, that there is a logical statement! So I can't trust it either! And so on... aaaAAARGH!
The more I try to find truth, the less I find I know. I somehow get even more agnostic than I thought it was possible to be, I at least thought, 'Alright, I have no idea what the universe is, but as an external observer I know that I exist.'
I am no longer an external observer! My observations about how my hormones and body affects my emotions, which in turn affect how infuriated I am at the fact that I don't know stuff, that I don't have free will - not the other way around - means I can't even think anymore, as my brain is part of the compromised system. I am compromised.
The more I learn, the less I know.
(This is not an attack on you as a trans person but an attack on your reasoning)
You say you are trans and that you don't trust your gut feelings and subjective observations?
Isn't gender dysmorphia based on internal feelings and observations?