This is obviously a complicated topic. I think the reason you are finding some resistance in this thread is that the essence of the questions you have is not very clear. When you say I want to know what has worked and what hasn’t in the past, I think you are giving people the idea that you are looking for a solution to cure gender dysphoria. In other words, it sounds a bit and analogous to pray the gay away method. Please note that this is not an accusation, just a possible interpretation that people are having based on what you wrote

My two cents on the matter: the Internet is a wonderful place, but on these kinds of topics, it’s mostly echo chambers. I think a clinic providing gender affirming care will also have extensive programs for family members and places where you can ask these questions. It is also very important to note that these places are not ‘transgender factories’, what I mean by that is fact that your child is going through the door doesn’t mean any hormonal or surgical treatments will allways be started by definition. But my feeling is that they will have the care and help that your child needs.

Lastly, really good of you to reach out in order to better be able to help your child through a difficult time. Remember to also ask them what they need and what they think they need regularly. Even if they don’t know it themselves, it is an important question to be asked because it lets them know you’re taking them seriously