At this point, we don't know that there was reckless malfeasance at play. However, there is plenty of circumstantial data to indicate that may have been the case. There was certainly an explicit and willful disregard for expert advice or battle-tested opinions. However, we don't have enough information yet (and may never get it) to conclude that was the cause of the accident.
It could be that someone/something damaged the hull (oceans and boats are notoriously hostile environments) and that created a weak spot that failed under pressure, or that some other mechanical failure occurred. However, those are both every bit as speculative as what I'm cautioning against. They are provided for illustration, only.
Could be? The whistleblower found visual defects in the carbon fiber before they even started using the sub. That's why they fired him. They eventually found more damage and repaired the hull in 2020/21.
It could be that someone/something damaged the hull (oceans and boats are notoriously hostile environments) and that created a weak spot that failed under pressure, or that some other mechanical failure occurred. However, those are both every bit as speculative as what I'm cautioning against. They are provided for illustration, only.