When doing any kind of risk assessment, even with access to all available data, there will always be the consistent variable of "we don't know what we don't know."
Is there a possibility that these vaccines can cause long term organ damage or neurological issues in a small subset of people? We don't know. We do know, based on the existing VAERS data that some people have experienced adverse effects in the short term post vaccination, including blood clots, anaphylactic shock and even death. What are the risk factors and what could be the root cause?
Is there a possibility that enabling the body to recognize the Sars-CoV-2 spike protein could potentially interfere with future treatments that may be necessary to fight a variant or another type of deadly virus or pathogen? Impossible to know.
I'm not saying any of these risks are likely or particularly high for the general population, but we have to acknowledge that there are unknowns and prudent people should always consider this before making personal decisions affecting their health.