Some endo don’t do P1NP when it comes to antiresorptives, especially powerful ones like Reclast or prolia. When your CTX is low at 74, most likely your P1NP is very low too so keep monitoring CTX is sufficient.

If you like, I can send you the link for a published review regarding strategies in withdrawal of prolia. It mentioned btms and bmd monitoring during prolia withdrawal, meds and lenght of antiresorptive treatment. But it does seem you are in good hands.