No. It isn't. VAERS just dumps people who have any medical condition at the time of vaccination. Neither correlation nor causation can be inferred from the data. The data has no reporting standards, no verifiability. It is not a study on vaccine side-effects (of which there have been many).

Using VAERS as proof of anything is a literal demonstration that the person in question has no idea what he's talking about.

Which is funny because the same people claim a lot of Covid deaths are from other medical conditions.

VAERS is basically a self-reporting facility for any adverse condition that occurred vaguely in the vicinity of being vaccinated, and its quality should be assessed as such.

In other words, VAERS data should be treated as at most a "this may be worth looking into," and certainly nowhere near a level of "this is a definitive proof something goes wrong." Especially in a time when tens of millions of people are getting vaccinated with the same vaccine at the same time, you're going to get lots of reports of people falling ill with something just by sheer coincidence.