Residency requirement for citizenship application

So here’s the thing:

I am an Italian/Taiwanese national without household registration, therefore I am in possession of a National Passport (Without ID number). Both my parents are regular national citizens.
Next year the company I work for will set up a rep office in Taipei which will employ me (as an Italian national) and sponsor my working permit allowing me to apply for an ARC. My plan is to stay for 3 years working in Taiwan.
Obviously this is the good chance for me (I will never have another chance to stay for such a long time in Taiwan) to fulfill the residency requirement (2 years for at least 270 days per year) in order to qualify for applying my Taiwan national ID.
My problem is… since my company’s rep office is going to hire me as an Italian employee, I guess I will need to enter Taiwan with my Italian passport. In this case how shall I demonstrate to the competent authorities that I fulfilled the residency requirement of 2 years for at least 270 days per year (which according to my understanding is determined by the entry and exit stamps which appear on the Taiwanese passport) for applying my Taiwan national ID?
Is it even possible under these circumstances?

Can someone help me clarify this doubt?
Thank you in advance.

You absolutely must enter on your roc passport and you must have a TARC for the time to count. If you are entering on your other passport then none of that time will count.

The employer arc won’t count so you should plan on getting a TARC followed by the open work permit.