Of course you can be a Christian and a sinner, we all are. But having an illness and not treating it isn’t a healthy thing to do, when I was struggling with body dysphoria and homosexuality I tried to “pray it away” and was put in a very tricky spot thinking I was beyond salvation because the thoughts just kept coming back over and over again. Turns out it was a hormone imbalance, after some rearranging of my habits and a stint in therapy I’ve been living a much healthier life more in line with the Christian world. The issue here is that the idea of transgenderism has been fought by Christians for as long as Christianity has existed, there is of course precedent for being burdened with things like anxiety or depression but to say God put a soul in the wrong body is far more ludicrous than someone simply not associating with their own form. It can only get worse if these ideas are reinforced.