Kernel 5.5-rc7 is out, and brief details are here: http://lkml.iu.edu/hypermail/linux/kernel/2001.2/04928.html
This includes e1000e: Revert “e1000e: Make watchdog use delayed work”, and I have tested this, and it appears to have – finally – fixed the problem.
Hopefully this will be back-ported to the next release of the 5.4 x kernel..!
Robert Gadsdon. January 20th, 2020.