1) Further thoughts - in my case with nvme module built in to kernel,
parameters can be set using kernel boot command line.

2) Also this may be useful, I found this tidbit from 2017 in case your
hardware has this:

ommit 07fbd32a6b215d8b2fc01ccc89622207b9b782fd
Author: Martin K. Petersen <martin.petersen@oracle.com>
Date:   Fri Aug 25 19:14:50 2017 -0400

     nvme: honor RTD3 Entry Latency for shutdowns

     If an NVMe controller reports RTD3 Entry Latency larger than
     shutdown_timeout, up to a maximum of 60 seconds, use that value to set
     the shutdown timer. Otherwise fall back to the module parameter which
     defaults to 5 seconds.