1 Unless we see real network rates, everything is based on hypotheticals. Sam mentioned iftop but I’d recommend ifstat that will provide a history of bandwidth used per second:
ifstat -nt -i eth0 >/home/osmc/ifstat.out 2>&1
Once you have collected enough data, you can then post it to the OSMC paste bin:
paste-log /home/osmc/ifstat.out
and make a note of when the error occurred.
2 I see you’re using a Kodi-based SMB mount. You might get an improved throughput using an fstab-based mount.