> Given the hundreds of millions of people that have received mRNA vaccines I think generally we have an understanding of their safety.

The conclusion does not follow from the premise.

Five months following a covid infection in which I had 4-6 weeks of neurological deficit, I received the bivalent mRNA booster, which seemed to somehow reactivate the neurological issues for a few days or a week. Doctors told me this is not uncommon.

These are not "safe" in the same way we mean that MSG or acetaminophen are "safe".

Corners were necessarily cut in the trials of these during development to accelerate time to market. They saved lives, the gamble paid off. But the trial protocols are in place for a reason and we do not fully understand these drugs as yet.