As for it existing for years… Pfizer for example announced the first risks in this regard April 2021, so about 3 years since they announced it. Of course you have to do studies first, so studies suggesting the risk were already availible sometimes before that, months to years.
So yea we can safely say this stuff has been public for 3-4+ years now in studies and even admitted and published by Pfizer directly for at least 3 years.