Would your mind explaining what exactly that INPUT_PULLUP does?
At the top of the forum web page is a heading "LEARNING". One of the menu items is "REFERENCE" and most of the basic syntax questions are answered there. There are listings for both pinMode() and INPUT_PULLUP.
The output of the hall sensor module is an npn transistor with open collector. It is basically a NO switch to ground, with a floating output when open (not switched to ground). In order for the Arduino input to read this properly, it needs a "pull up" resistor to a HIGH level voltage when open.
this pullup resistor can be either the internal resistor engaged with INPUT_PULLUP or an external resistor. The internal resistor is about 50K, and my not provide a strong enough pull up to HIGH. An external resistor can be of lower resistance 4.7K to 10K is frequently used.
Google will be your friend for any terms you don't understand.