AFAIK a slightly smaller screen with higher resolution is about all the difference there is between the Ubook X and Pro (the X being the smaller/higher resolution one). The biggest difference is with the keyboard.
Probably because the batch of screens Chuwi ordered for the Ubook Pro-model was depleted and they couldn’t source the same panel anymore, so they just made a “new model” of the Ubook-line that’s basically the Ubook Pro but with another display.
Although nice to know the charging via USB-C works! I was in doubt to order a powerbank like the ZMI 65W-model because I didn’t want to fry my pretty tablet (which I use daily for about all my digital consumption and teaching), but now I know it should work