Lack of evidence isn’t proof that intelligent life didn’t evolve multiple times on Earth.
Similarly, lack of evidence doesn’t prove that the dark side of the moon isn’t populated by dancing magical unicorns that pee rainbows and poop skittles.
Lack of evidence doesn’t “prove” anything.
Absence of evidence isn’t evidence of absence.
But there certainly isn’t any evidence that intelligent life evolved prior to humanity any time in the history of the Earth.