Where is the write protection screw on this model?

Protection screws are generally near the main processor on the logic board. Note that most of these laptops will have a metal cover that acts like a heatsink. Under the metal cover one screw hole may have a sticker blocking the screw or cover from shorting the contacts on the logic board to disable write protection of the system software.

Another one is that it may be using an opposite way to disable where you leave the screw out as well or put tape to block it from shorting the board.

Should be a mark on the board where it looks like it may be bridging the contacts as shown in this picture:

https://memcpy.io/images/2017-02-27_wp_s...

If you see any similar to that you either need to unshort the contact or short it to disble write protection. Either by covering it up or removing the cover.