My FB ADs did work fairly well. Recently, after the IoS changes and the new Meta Processes, the ADs became useless. After several revisions to improve performance, I stopped them all with the intention of coming back when FB/Meta figures out their new AD processes.
Shockingly, FB/Meta has reached out several times to meet and discuss how to improve the ADs. I finally accepted, and scheduled a meeting.
The "account manager" cancelled an hour before we were to meet. Several days later, she asked me to reschedule, gave a few time options, I re-booked. She came back and told me the time slots were no longer available.
Consequently, FB/Meta ADs are no longer on my to-do list.
R.C.