grimslade
Krampus ate my d20s
My preference is for a new system for Psi because 5E can handle it. The sorcerer is an absolute hash of a class. Build a more flavorful sorcerer and call it the Psion/Psionicist/Mystic/Jedi/Master of the Way.
At this point, I would lean away from psi as a new class or subclasses. There is too much argument over 'but mah wizard" and 'Dark Sun will die because of you Wizard lovers'. There is no consensus possible. We have seen too many threads devolve into bickering. Possibly look at the UA for Strixhaven with replacing class abilities depending on College. Add psionic powers to existing characters, by using the framework of 5E.
At this point, I would lean away from psi as a new class or subclasses. There is too much argument over 'but mah wizard" and 'Dark Sun will die because of you Wizard lovers'. There is no consensus possible. We have seen too many threads devolve into bickering. Possibly look at the UA for Strixhaven with replacing class abilities depending on College. Add psionic powers to existing characters, by using the framework of 5E.