Not the first
If we leave the Galaxy Z TriFold to the side for a moment, even if Samsung does launch the Galaxy Z Tab, Galaxy Z Fold Tab or whatever it calls it, it won’t be the first to market (though getting ahead of the possibility of Apple doing it is likely in Samsung’s mind).
Lenovo has the ThinkPad X1 Fold, which it calls the “world’s first foldable PC”. It’s got a 13.3-inch screen which can be used with a pen, keyboard, or fingers. It folds inwards like a book, so doesn’t have a smaller display mode.

Hersteller falls nicht anders angegeben
Huawei launched the MateBook Fold (above), which has an even larger 18-inch display. It works in effectively the same way as the Lenovo, so it’s like a laptop where the keyboard section is also a screen. The firm may also be working on a smaller 8-inch foldable tablet.
Whether Samsung can make one similar to these but with a smaller display option to make it more versatile remains to be seen. And if it does it might not arrive any time soon, but we’d certainly be interested to see how it works, what it brings to the market and if anyone buys it.