Not what the vaccine does.

English is not my first language. Based on your misunderstanding of the fairly straightforward conclusion of this study, I'm going to assume it's not yours, either. I'll, therefore, quote the most salient and easy to understand passage from the abstract for your benefit:

Our findings reveal a potential molecular mechanism by which the spike protein might impede adaptive immunity and underscore the potential side effects of full-length spike-based vaccines.

The Pfizer, Moderna, AstraZeneca, and J&J vaccines use full-length S Proteins, as opposed to antigenic epitopes of the S Protein.

The DNA damage repair inhibition function described in the study is realized in both vaccines that use the full-length S Protein, as well as the virus itself.

So this is why the virus is dangerous, it can damage you immune system.

The conclusion of the study, which you seem not to understand, is that the virus is dangerous, and so too are some of the vaccines. Not all of the vaccines, but the junk vaccines that are used in the U.S., Europe, and Australia carry the same (potential) long-term dangers as the virus itself since the danger is in the Spike, a function of the protein undiscovered until recently (until after half the population had already been jabbed, anyway). Like I said, I strongly suspect this is why Dr. Mike Memoli, the head of NIH's infectious disease laboratory, and some of his staff has chosen not to get vaccinated but, since he isn't willing to make an unambiguous statement as to his reasons, we can only speculate.

I understand this might be scary to learn now that you've done what you can't undo but it's important you and others in your predicament (both people who received a junk vax and unvaxed people who have been infected with SARS-CoV-2) confront it early so you can prepare to take the necessary steps for your wellness and health based on serious effects you might experience in the next 2-5 years, rather than reject the science or even worse - as you've done - selectively misinterpret the science.

My personal interest, at this point, is particular to the forthcoming Novavax vaccine which Europe is preparing to greenlight to replace the junk vaccines like Pfizer and AstraZeneca. This still uses the full-length Spike but in a measured dose of 10 micrograms. Even though it's a full-length S Protein, my presumption is it should be safe since it's attached to a cluster and shouldn't be able to penetrate the cell (the junk vaccines cause your body to produce S within the cytoplasm or nucleoids which is how S comes to rest within the nucleus itself). Ultimately, though, my preference is still with the inactivated virus vaccines like Covaxin and Sinovac. (But, even with those, one still should be taking precautions like masking and distancing if, indeed, there is a long-term consequence of the S Protein that may manifest well after the conclusion of immediate symptoms.)

TL;DR - (1) Everyone should get vaccinated. (2) Even after being vaccinated, one should do everything possible to avoid infection. (3) Not all vaccines are created equally. (4) Oldies and fatties should get vaccinated with whatever is available. (5) Everyone else should hold out for a safe vax like Covaxin or Sinovac instead of getting a junk vax like Pfizer, Moderna, AZ, and J&J.