There may be others out there — but we’re not likely to ever meet them.
Nope.
You remind me of the people who wanted to close the patent office after in the late 1800’s because everything was already invented, after all we had the steam engine!
Has you ever considered we may not know everything there is to know about math and science? And FTL travel may exist? (and is already been proven mathematically to be possible)
Besides, Bob Lazar told everyone the government already has alien spacecraft with gravity-propulsion systems, and I believe him (seriously, I do)