The amount of times I've been online and misdiagnosed myself, man I don't even know. Worst case was I convinced myself I had afib. Knew it, from all of my reading and everything I had all the symptoms.
Except I didn't have them, because since I've never experienced the symptoms I thought I had the symptoms, but I did not.
The knowledge isn't "gatekept", it's not something they hide away in a chest. It takes 10 years of medical school and several more after that of on the job training just to be a junior doctor. Talk about minimizing how complex the human body and all possible ailments are. We go to doctors not for the 15 minutes in the exam room with them, but because of the decades of knowledge they learned so we didn't have to.