Until such a time that reliable scientific proof is provided all these fear mongering antivax conspiracy bullsh!t theories remain just that.
And one can only feel sad that people fall for this idiotic sort of nonsense.
I follow several and not one sports player has died from a blood clot caused by a vaccine in any professional team I know of. There have been a lot of people getting Covid even after being vaccinated but only mild to light symptoms from what I have seen and read.
Fear mongering doesn't do anyone any good, it just makes simpletons out of those who swallow such lies and nasty people of those who knowing better spread lies.