I've attached a link to an article about how VAERS works, but here's the short summary that should clear up your confusion about it:

AERS is intentionally set up to capture adverse events that are not thought to be caused by vaccines. It is the best tool we have to find what may be previously unrecognized and extraordinarily rare adverse events that may eventually be linked.

VAERS cannot and does not determine whether a vaccine caused something. The CDC states this clearly in their disclaimer: "A report to VAERS does not mean that the vaccine caused the adverse event, only that the adverse event occurred some time after vaccination." The disclaimer continues, "The reports may contain information that is incomplete, inaccurate, coincidental or unverifiable."

https://www.nebraskamed.com/COVID/does-vaers-list-deaths-caused-by-covid-19-vaccines