The trick is to perform the Ritual of Rebirth and become a dragonborn. Then do it again and again until you have 0 Dex and massive Con. Make sure the last ritual grants you a breath weapon.
Since psionic powers don't have components, you can still manifest despite being unable to move. In emergencies you can use animal affinity.
The ritual of rebirth just makes you a dragonborn.
If you're a dragonborn human, it'll turn you into a dragonborn human.