The Vivo company seems to be going to introduce several different smartphones with flexible screens at once. Moreover, they will be different, including the form factor.
This is hinted at by the company’s registered trademarks Nex Fold, Nex Slide and Nex Roll. It is easy to guess that the first one will be a foldable device either in the form-factor of a book or in a clamshell form-factor, the second will be a slider, and the third will receive a roll-up display.
There are no details, but Vivo’s Nex line has always been flagship. In addition, flexible screens are still often the prerogative of top-end devices.