I agree that shunning and isolation are the biggest obstacles. More important than all the other things mentioned. I don’t consider critical thinking a hardship. I think I used it inside and outside JWs and always felt comfortable doing so.
I also have big problems with the idea of “authentic self”. Basically I don’t think there is any such thing. We have the ability to change due to circumstance or effort or necessity to some extent. But I don’t know that it is helpful to label this or that “authentic”. In fact if I was to pick my most “authentic” self ever, it might be me as a 14 year old boy who loved going on the ministry and was totally convinced this was the truth. That was completely authentic for me at the time. I was happy and comfortable in a way I have never been since. It would not be “authentic” for me now, because I have changed.
Anyway, I find the idea that JW life is inauthentic and the new existence outside of the religion is authentic to be problematic, in that I find it to be neither true nor helpful.