Is your bootloader unlocked? If yes, try to reflash the stock recovery or para partition, because there may be a flag to do a factory reset (and this TWRP is not able to remove this flag)
Yes, I thought it was necessary to unlock the bootloader to flash TWRP? Is this not the case for this device?
The 3C Toolbox app allows you to set any orientation (including built in tablet sensor orientation) for any application.