NVT I2C bus capacitance
50 pF is load capacitance in this case.  It's the bus capacitance downstream of the level shifter.  Further in the datasheet you see CL(tot)= 50 pF in a few places.

197 Ω is a very small pull-up resistor.  Typical I2C slave device can't pull against such a stiff pull-up.  I suspect you would need a weaker pull-up.

50 pF is a fairly small value for I2C bus capacitance.  If you have a larger bus capacitance and weaker pull-up, you should still be able to use this level shifter at a slower bus speed (the usual 100kHz or 400kHz).