4 years later the second doctor asked me "I wonder why did my colleague decided not to take a tissue sample from insert some place in the stomach. I said out loud "I didn't even know what that is, let along ask him why he didn't".
No, that's not the same way that anyone lacking knowledge gains confidence in the things that others tell them.
A technique one can use instead of blindly trusting what one person may tell us is seeking out second opinions to corroborate new info. This works for many things you might not have personal experience with: automobiles, construction, finance, medicine, &c.
Some random redditor ended up figuring it out. Then every physician from that point forward agreed with the diagnosis.
Licensed based medicine :(