Latency is still latency, though.
You can shrink the processor as much as you want, but the more processing power you pack into that AirPod or smaller device, the shorter the battery life.
That's why you'd have your phone handle the heavy-lifting in the processor department.
The "Me Too" products will, of course, be the junk that's sold on Temu or similar for a fraction of the price, and doesn't have the functions that the expensive ones to, even though the listing 'claims' to.
The legit ones will still be well out of range of anyone, the same as an unlocked Galaxy S28 is to someone flippin' burgers.
If this hearing aid actually is controlled by the brain (somehow), it'd basically be Sony's Zoom Mic contained in a hearing aid... that'd be cool, but you'd have to shrink the hardware significantly and have enough battery life to last the typical day (not have to recharge every 4 hours, because the thing can't have a sleep function).