Modern dumbphones exist: https://www.hmd.com/en_int/nokia-3210
I mean, sure you can find them if you look hard enough, but a phone that plays videos is not a dumbphone in my book. And I wouldn't hand it to my kid. It's probably worse than handing them a smartphone, because I'm guessing it is just dumb enough to have no parental controls.
Of course they do. But this is HN - not as neat as using the 15-year-old phone I have.