This is still a quagmire for modern scholars, made even more difficult by the paucity of surviving texts from pre-Roman Iron Age Spain and before the dominance of Latin. With the exception of the Greco-Iberian alphabet that was basically just an Ionic Greek alphabet tweaked for native Iberians, the Paleohispanic scripts weren't even purely alphabets or even purely syllabaries but rather semi-syllabaries that combined both. This makes it difficult to judge whether or not the Phoenician alphabet was the sole source of inspiration for these alphabets or if the Greek alphabet played a smaller or even equally influential role. What do you guys, think? The fact that the Greek alphabet is based on the Phoenician one certainly doesn't make it any easier to discern which one served as the model for the Paleohispanic scripts. These were not used just for the native Iberian language either, but also for the Continental Celtic language of the Celtiberians, who had their own script based on the Northeastern Iberian one.
I have my own hypothesis, though!
Like the primary writing systems of the ancient Shang-dynasty Chinese, Mesopotamian Sumerians and Early Dynastic Egyptians that spawned hundreds of others, the native Iberians invented writing all on their own!
Unfortunately nobody subscribes to my hypothesis, at least not until I put a gun to their heads and make them see the light. It's time for you to accept my hypothesis, or you can just go ahead and die. Your choice pal.