No idea whether this holds up, but the human body is all about conditioning and maximizing energy efficiency, so it should at least be unsurprising if true.

My vehicle has a number of self-driving capabilities. When I used them, my brain rapidly stopped attending to the functions I'd given over, to the extent that there was a "gap" before I noticed it was about to do the wrong thing. On resumption of performing that work myself, it was almost as if I had forgotten some elements of it for a moment while my brain sorted it out.

No real reason to think that outsourcing our thinking/writing/etc will cause our brains to respond any differently. Most of the "reasoned" arguments I see against that idea seem based on false equivalences.

This is why I am not so concerned. I am old enough to remember when teachers thought that outsourcing calculations to calculators would atrophy my brain. They said the same about computers. Then the internet and Wikipedia. On one hand, yes, I am slower at calculating things by hand. On the other, it doesn't matter anymore. I am much faster at getting things accomplished. AI might just be the latest way in which humans are exploring transhumanism. Perhaps we are irreversible altering our brains. I'm just not convinced that's a terrible thing.