Would PDO be effective if Sculptra had no effect on me?

Nothing, not even threads, lift the face at all, not even a little. The companies that make PDO threads and the 'healthcare providers' that market and use them are all involved in fraud, and are relying on the placebo effect to con you into thinking there was a result. We learned 15 years ago that permanent threads had no effect by 6 months; it's not any different for resorbable threads. Volumizers like hyaluronic acid gels (Juvederm/Restylane/etc), Sculptra, Radiesse, and Bellafill don't lift either, and are the primary agent for making someone look bizarre when used in excess. They are great when used properly, but when a lift is needed, nothing else will suffice except surgery.

Dear Christalent,
I have responded to your other question and can only answer in general as I have no direction in the results you are trying to accomplish nor any idea what facial issues you are concerned about. Please:
1. Consult with a talented and artfully skilled Board Certified Plastic Surgeon for a hand-on evaluation and which of the non-surgical, minimally invasive and surgical options are best for you.
2. That said, consider
a. Non-surgical Retinoids for skin turnover and collagen stimulation and then mid-depth TCA peels.
b. Minimally invasive: Sculptra for firming and tightening (not as you mentioned volume and lifting)
c. Minimally invasive: PDO or PLLA barbed thread suspension sutures for lifting; BUT the amount of collagen production throughout the face is minimized due to the minute thinness of each thread. Intradermal PDO or PLLA thread meshing will provide a better resistance and wrinkle reduction.
d. Surgical lifting.
All the best with your rejuvenation journey.