All the Pilots I have flown with instinctively trimmed their aircraft, they did not have to work out or analyse why it was needed; in the B737 Stab system, even if they could not hear it above the other noises, they would know it was moving, it is next to their knees and, as I understand, it was not just creeping around with the MCAS input.
Something more dramatic went wrong to cause the steep dive, be it health related or a mechanical failure.
If only to keep the options open for discussion, as the elevator input cables are designed to take full manual input loads, when there has been A&B hydraulic failure they are unlikely to have broken during this flight but what if?