My and my family’s experience with flu and flu shots does not conform to the research in your post.
I had a flu vaccine only once more than 50 years ago while in the Army. My body’s reaction was that I wound up in the hospital for two weeks with severe URI issues.
Meanwhile in all the years since I have never again had any flu vaccines and never once had a sever case of the flu. And
my case (other than the bad reaction to the 1st flu shot) is the same as for all three bothers of mine.
Meanwhile a sister of mine and her daughter have had the flu vaccine every year since her daughter was in school. And every year they each have a sever flu illness.
I do not believe that “original antigenic sin” is as overpowering as the article suggests nor that adaptive immune abilities are so weak nor so ill designed as to not adapt and build on prior experience. The later point seems to me to be more likely, and the more sensible a natural design.