Hi

I have been using a Spark Smart Modem 2 for awhile on a fibre line. It was a nightmare trying to find stable settings for it, but I think hard setting it to Ethernet for WAN, rather than leaving it on Auto has helped a bit. I still have intermittent issues with this device that really make me miss the older modem and it's stability. Usually when it fails on me all traffic stops and I cannot get to the modem management page to even diagnose, I just have to restart it. Is anyone else using this thing on fibre and found it stable or otherwise?

I think the firmware leaves a lot to be desired too:
I wish I could disable/enable NTP, logs seem to regularly complain about NTP.
I wish I could turn off TR069.
I wish I could set the DNS I want to hand out to DHCP clients.
Etc.

Mainly I just want a device that is stable and reliably provides service. I currently have a white status light and my Wan status in the console reports uptime of 1second. Refreshing this page the ntp time updates, the wan status uptime does not. 
My current system uptime is 2 weeks, maybe a record, but yeah I don't think my fibre line is the problem. If I switch back to an old Asus AC68 router that was more reliable, even if much older. 

Is this device only fit for purpose on a Mobile WAN link? If it can be relied on to provide stable service on fibre, what are the tricks in config to achieve that?

Thanks.