For me, I am in the same position as you (Keri). In person, no problems. Over the phone, the misgendering happens more often than I'd like. I know that this surgery is only one step of my voice training process. I would say that the surgery is already perfected. It's just 1) how it's performed, 2) the person's healing powers, and 3) environmental factors that are the variables. That's a lot of variables and they apply to any surgery.
In the case of 1, if the surgeon has a bad day, a stitch could end up a micromillimeter in the wrong place and that could affect the outcome.
In the case if 2, a slow healer will certainly have a longer period of wait time than a fast healer. If the person smokes, drinks, eats certain kinds of food, that may affect the outcome.
In the case of 3, if the person accidentally or conscientiously talks or utters sounds during the crucial period of silence, that could affect the outcome. It seems to me, from what I've read in this forum, the period of silence is different for everyone. Outside factors beyond a person's control could also affect the outcome. For example, somebody smokes near you and you start coughing because of it or you eat something you're allergic to.
Like others here, I would say do the surgery for yourself, not for anyone else. Everyone I know tells me my voice is fine, but I'm not comfortable with it. That's why I'm going for the surgery.