I wonder what kinds of places you've been reading these articles about pleasure? Because you've talked a lot about different physical things, but actually a lot of what is going on when people experience sexual pleasure (regardless of their gender or anatomy) is their brain. This is a good place to start if you want to understand what I mean: With Pleasure: A View of Whole Sexual Anatomy for Every Body
You're mentioned hating your body and experiencing pain a lot - neither of these are going to make for a great headspace for experiencing pleasure. Can you expand on what you mean by being mad at your own body?
It sounds like anything entering your vagina is quite an ordeal for you, what if you put that on hold for now? We can talk more about why that might be if you like, but I don't want to throw too much at you at once just now! You're definitely not alone in finding vaginal stuff not-pleasurable, so you're not weird or different.
There are a couple of fact-checks I do want to do though.
1. Women and people with vulvas can and do experience sexual pleasure, and I have no reason to believe that whether you have a vulva or a penis affects how much pleasure you can experience. Usually the problem is that we're looking for it in the wrong places.
2. I'm not sure where the pregnancy thing came from but we actually have MORE nerve endings in our clit than there are in the head of a penis. It's inside the vagina itself that a lot of people find less exciting.
3. You're also right that in most of the 18+ content you're watching, most of the pleasure is probably fake - from everyone involved. The people you're watching are actors doing a job, and it's not hugely representative of real life.
Does any of that surprise you, or make you think?