EVs are older, sure, but they were in suspended animation for a long time.
As to the question of how mature is mature enough, that depends. In my case, as an EV owner, I think they are mature enough now. However, the fact that major developments in range, efficiency, charging speed, etc are happening regularly in the EV space reflects a certain immaturity. The technology clearly has not yet stabilized, and that may be concerning for people coming from an ICE background.
As noted elsewhere in the thread, they do support MTP transport, so it’s definitely not as user-hostile as it first sounded. Things like Calibre will still work. However, the fact that Amazon also removed the ability to download ebooks in the browser for offline transfer suggests where things are heading. IIRC kobos have some anti features of their own, but I don’t recall the details. I wonder if something like the Daylight DC-1 could be even better. It’s not just a nice reader, but a proper computer. At least, if it actually exists.