How difficult is it to safely hop on?

I'm 30, been training 10 years. Of those I'd say about 3 years consistently and 7 inconsistently. But quite consistently for the last 1 year. I am not thinking of anything crazy, just some test, but whilst the whole thing seems insanely complex and involved, I see so many young people do it. And not to be judgemental, I can't imagine these kids in HS or early college or the average dude at a rave on 250mg of MDMA is so knowledgeable about the biochemistry and medical knowledge that goes into this.

Admittedly it's not my field of expertise, but I have a PhD in a field that requires a lot of statistics and mathematics, so feel I can learn science-related topics with at least some degree of competence. Yet it also seems very complex. The frequency of administering the hormones, sourcing them, doing PCTs, bloodwork, what to look out for, how to adjust, using AIs or not etc. I mean the background knowledge required to properly understand these things is pretty complex. I have read through the wiki, I have read through questions and posts here.. even some sections of TRT books. I feel like I would need to properly study for 8-12 weeks to feel comfortable that I at least somewhat know what is going on.

Do most people just have some sort of cookie cutter protocol and a few significant things in their checklist to make sure they are okay? Do people just learn it as they go? Is there a wide safety margin of error before people really fuck up? Are there real dangers of the reliability of a source, i.e., not actually receiving the compound you ordered and having no real way to confirm it's reliability other than administering it?