The autism vaccine thing is more from childhood vaccinations than the one for the flu, and is probably a load of crap. Guillain-Barré syndrome is what the flu vaccine can give you on rare occasions, or that is my understanding anyway.
I am a bit over 50, eat a healthy diet and am physically active. No medical problems or medications. I can count the number of times I have gotten sick since 1975 on one hand.
Got vaccinated for pretty much everything when I went in the Navy, bubonic plague, typhoid, pneumonia, flu, everything. Sick as a dog for a week.
5 years later, got food poisoning in college. Felt like I was going to die, afraid it would not happen fast enough. I can't recommend it as a weight loss technique, lost 20# in a week, sucked more than somewhat.
6 years after that, was compelled to get the flu shot going to grad school. Was too sick to get out of bed for 3 days. The following year they said I had to get the flu vaccine again. I declined. They told me I could not work in the clinic without the vaccination, and would not graduate if I did not work in the clinic. I told them I would sue them for the price of my education if they tried that, and they caved immediately.
10 and 12 years later, got food poisoning again on two different occasions, sick for a day each time.
So in the last 40 years have been sick 5 times. 3 times eating food someone else prepared, twice immediately after getting the flu shot.
With the lead time to produce the vaccine, they guess what the predominant variant of the virus will be next year, and make a vaccine for that. They guess wrong a fair amount, and I have gotten extremely sick every time I have gotten the flu vaccine. Consequently, I don't get the flu shot, ever.