But minarchists are also libertarians. Libertarian is quite wide term. It also may include left-libertarians (anarchists).

Well it depends on your gender dysphoria. Different people have different levels of dysphoria. I described generic case when you are free from misgendering from government when you don’t feel pressure anymore and can reconsider your HRT (but of course it depends on many things).

Viagra is just a fancy name for Sildenafil. So it’s basically the same thing. Rising testosterone level will help but I recommend it only after legal gender change.