I bought and returned a 13" iPad Pro M4 because I couldn't get a Smart Keyboard Folio for it. Only the Magic Keyboard is available. I'm still using my 2018 iPad Pro.
Same, I actually bought a few of the Smart Keyboard Folios to use as they die. Upgraded to the M2 iPad Air, as I think it's the last of this form factor...
It is just such a shame they discontinued the keyboard. It makes for the perfect iPad with a full keyboard.