If Wikipedia is to be believed, that's smaller than many of today's smartphones (apart from the 19mm (!) thickness). Not really a tablet, despite the name. https://en.wikipedia.org/wiki/Nokia_770_Internet_Tablet

I would believe that most phones these days are bigger than an old tablet.

Heck, some phones reaching the size of my Nexus 7!

By diagonal screen measurement, yes. The Nexus 7's aspect ratio makes it much wider than phones though (120mm vs ~70-80mm). A 7" smartphone is likely to have almost no bezel too.

Oh, completely. My Nexus 7 had a 7" screen, while the iPhone 12 Pro Max is 6.7", and the Galaxy S 21 Ultra is 6.8".

My Nexus 7 total size was more like 9" diagonal due to bezel.