Hmmm. If every 5E class has an influence that would match with modern tastes (ala people in their teens up through early 30s), let's look at kind of subclasses the Psion might have. After all, the base classes are usually generic in fluff with a handful of exceptions. "Adventurer who prays a lot." "Adventurer with a magic book." "Adventurer who loves to be outdoors." So, the Psion being the "Adventurer with a lot of brain power" is a good enough generic base I think.
Off the rip, I have three subclass inspirations.
Bene Gesserit from Dune are amazing Psions. THis could be the "gish" Psion subclass, like its Eldritch Knight/Bladesinger. A Psion who uses their mental powers to manipulate physical bodies, not just their own but others as well. Biokinesis, basically, but on a more restrained, subtle, and manipulate scale. Little science fantasy would be good here.
Next, a Force User from Star Wars. This is a psion who uses their mental powers to take hold of reality to move things about (telekinesis), influence others, dominate minds, and so on. This would probably be a Psion who can use their psi points to cast enchantment spells, and who can even use their mind's to bend the world, thus allowing evocation spells, etc etc.
Lastly, we have our traditoinal "Professor Xavier" mystic. This is a powerful telepath who can install illusions into people, maybe if a creature is unconcious this psion can install "programs" into them that they follow when they wake. They have stronger mental defenses from the other two, and can even augment others with their mind, maybe increasing their saving throws and so on.
Core Psion mechanic has Warlock slot progression and Psi Points comparable to Monk/Sorcerer. Psi Points fuel class abilities (True Psionics) that you get to pick like Eldritch Invocations. These abilities you spend psi points on to increase in power, though they have cantrip levels too. Then you have spell slots for when your mind is bending the weave to make magic and so on.
That right there is a flavorful, distinct Psion D&D class using Sci-Fi and Science Fantasy inspirations that I think deserves to be put into this game.