The Treo 180 and 270 were the first integrated touch/phone devices. The former was monochrome, the latter colour. I had both. Both had keyboards. Graffiti™ was introduced with the PalmPilot (and the USRobotics branded device, back when modems were a thing) and subsequently carried across to the likes of the Tungstens, which were excellent in their day. It still wasn't the slab format, though. Palm's Treo 650 was the closest they ever came and, yes, it had a keyboard,
As for the Newton, least said soonest mended. The fact remains that the XDA was the first of what we now recognise as the de-facto standard format for a smartphone.