You're asking the wrong question.
You're asking: "are HRT medications perfectly safe?"
You should be asking: "are HRT medications of comparable safety to other OTC medications?"
And the risks from HRT medications are vastly overblown, which you are doing here. You're spreading FUD about HRT. The risks are lower than most OTC medications. And most of the "risks" cited by folks are just your risk profile switching from a testosterone-dominated risk profile to an estrogen-dominated risk profile. Trans women on HRT get an increased risk of breast cancer, no shit. Growing boobs will do that. Or look at the bullshit told to trans men about how it increases their risk of heart attack, when all it does is raise the heart attack risk closer to the cis male range than the cis female range. Almost all bullshit spread around about the risks of HRT are just your medical risk profile undergoing a sex change. Cis men are more at risk from certain maladies then cis women, and vice versa. When you go on HRT, you switch sides of this.
And this is the disgusting hypocrisy of it. (On the part of the medical establishment, not you specifically.) No cis man who hasn't already had a heart attack would ever be told to take testosterone blockers to lower his risk of heart attack, even though they absolutely could lower their risk by doing so. But when a trans man takes a medication that simply raises his heart attack risk to be closer to the male range than the female range, suddenly that's fear mongered as some horrible risk factor that needs to be guarded against at all cost.
Quit spreading FUD about HRT. It's safer than tylenol.