The first link, which you have to assemble by adding the part that the parser clipped, addresses your concerns. The others, including the summary build a position for better understanding (study) of igG4 (first paper identifies 4 subclasses of igG4).
You appear to live in a world of assumptions so you can puff out your chest and blow past legitimate observations. I found it enjoyable that you're hiding behind "for health professionals only" and "hypothesis" as if I don't understand what a falsifiable hypothesis means in this context.
It appears you aren't all you think you are, nor am I less than you.
Multiple studies show IgG4 increases following repeat boosting with mRNA COVID vaccines. That's indisputable.
Exactly.
"Increased levels of igG4 from repeated mRNA vaccination appears well correlated."