In my youth I was able to consistently enter flow at will during multiple activities, but especially making games, and increasingly so as I was getting better at it.
That eroded away with time, and these days it's extremely rare I find myself on the other side of a flow state. I think it's because I have much more on my mind these days, so I don't allow myself to really fully commit to something for a longer while. So I feel you on the having to defend it aspect, but for me it wasn't really LLMs that prompted it. It's more growing up and extraneous circumstances.
Basically as soon as I got a real job in tech, and the business aspects trumped every other consideration, creativity went out the window, and there's only the occasional mildly interesting problem to solve. In contract work you are rarely incentivized for doing the best possible job. Doing a middle of the road job yields more billable hours. And that's just not an interesting problem to me.
So I find flow elsewhere in my spare time, as rare as it may be. But it may be high time for me to condition myself a bit to allow myself enter flow more often again.
(Btw. the colophon on your website has a typo. The font is called Inter.)
8000 hours of Dota 2 had many hours of flow state as the player however..