The number of Covid jabs someone has had correlates with their vulnerability to infection, and especially to age. The older someone is, the more likely they are to die from all causes and from covid. Vaccine refusal/hesitancy correlates negatively with age:
Hesitancy towards the coronavirus (COVID-19) vaccine based on the Opinions and Lifestyle Survey covering the period 13 January to 7 February 2021.
From the time that vaccines became available, until the emergence of the omicron variant, the unvaccinated were far more likely to die of Covid than they are now. Now Covid is a milder disease, and it bears less resemblance to the original Wuhan strain of the virus, so the vaccines are less effective. It does not mean that people are dying from Covid because of the vaccines. It is that vaccines confer less of a protective effect due to the change in the virus, the milder nature of the virus means fewer unvaccinated are getting seriously ill with it, coupled with the fact that most people have by now had prior exposure to one or more strains of the virus.
I dare say that vaccine refusers tend to be out-and-about more and less likely to take any precautions against the disease, so are more likely to have been exposed before than the average person. You can see in the same dataset that informs the article above, that there was a time in the not-too-distant past when the balance of risk was heavily against the unvaccinated.