FibreX intermittent outages Wellington. Is it me or Vodafone?

I have been reading the gigabyte fibre forums looking for solutions but have struggled to find a concise summary of what is causing problems.

I recently upgraded to FibreX Max in Wellington (Lyall Bay)

Surprised to find my Nighthawk R8000 disconnected and the HG659 in it's place.

Have since turned off the HG659 WiFi connected the R8000 in bridge mode and using that for WiFi

I also have a LinkSys AC2300 in bridge mode downstairs (hardwired) to provide WiFi to the bottom floors of the house.

Initially pleased getting the expected 900+ speeds on Ookla on Ethernet connected PC's about half that 450 on Mac's.

However since the 15th of December have been getting multiple outages, no error message on any of my routers, just "hanging".

Problem seems to be with the Optical Modem and connection issues there. Vodafone has sent around a technician who changed the connector to the house, changed the faceplate and new cables. However, problem continues with 5-6 outages per day. Some <1minute some 10-15. minutes. As we do business from home this is very inconvenient loosing our cloud connection all the time. I'm looking for answers, as currently Vodafone seems without any.

At one stage I was rebooting the Modem and the Router but now I just leave it as it always "comes back"

1. Is this a problem at my end, I have read in some forums that the HG659 doesn't like more than 20 devices. We are close to 30.

2. I know how to make my R8000 work as the principal router, should I use that instead of the HG659, though some forums state that this may decrease speed.

3. Does anyone know much about the optical modem (Techicolor) and whether changes to it could be of benefit.

I would appreciate any help and hope that this post becomes a summary post for solutions.