Pemberley,
You and your daughter have climbed some mountains ... no wonder you are exhausted. But the hard journey up makes the view so much more precious. It sounds as though you have provided your daughter with great support and scaffolding, and she has developed strength, resilience and grace. I would call that a far more meaningful and durable success than the 'bling' of showy accomplishments. Those for whom the journey is difficult often take far more true pleasure in each small step, and they are not dissuaded by stumbles.
fwiw since I have seen you mention it on other threads, eosinophilic esophagitis is sometimes correlated with connective tissue disorders. While the geneticist may not have been able to identify anything obvious, this might be an avenue you could investigate if you are driven to know "why".
On the musical theater front, if your daughter's speech makes it difficult for her to take a leading role perhaps she could look at different paths - e.g. into directing.
But now what? How do I make my peace with the fact that things will never be easy for her, or normal for her? That no she will never have a level playing field? ... She and I have both worked so hard for so long - what do we have to looked forward to?
She is unique and brings an original perspective. That has enormous value. Comparing to others is not a good approach and overlooks the private battles they may be fighting. Don't dwell in that alternate reality. Your daughter has mastered skills others may never imagine, developed resources and creativity beyond their reach, and has depths far beyond what they have seen. The world is what she makes of it and she will find her path.
Hang in there.
