Hey bill888 thanks for the quick reply. Yes even once the issue with the bridged mode came up for me on the Netgear OEM firmware the internet would work in router mode. That was part of my frustration because once I confirmed that was working, I just set the device to modem mode which locks down all the configurable settings on it, but my Orbi would no longer detect it had internet and on the Connection Status page it would show it wasn't getting an ip address from my isp and seemingly stayed in a constant disconnected state.
Ok I've had a look at the guide you suggested. I was able to follow the steps in the guide up to a point/ I set the Annex type to Annex B based on discussion here, specifically the last comment and third last comments. However this Australian isp modem settings guide is not clear to me and looks like it suggests A or B depending on circumstances I don't know. I've left the tone on auto as I wasn't certain. Potentially it should be B43 + B43C but hopefully auto will take care of it? I've set encapsulation mode to PTM/EFM as per the HH5a guide, and the DSL line mode is set to VDSL. I've followed the remaining steps, clicked Save and Apply after each relevant step then finally performing a reboot then a power cycle. When the dm200 comes back up the only change in the DSL Status section is that the Line Status changed from Idle request to silent and the unavailable seconds value had changed from 0/0 to have some numbers in it (this last part isn't shown in my screenshot of the DSL Status as that's from before I attempted the guide you suggested). I tried changing the Tone to B43 and B43c and power cycling the dm200 but I couldn't see any difference.
I had a look at section 7.32 but I couldn't really make sense of it or understand if there was anything it was instructing me to do, it seemed like it was just suggesting that error is normal and will clear once the dsl sync occurs.
Here's some screenshots showing what I set.
From what I can see perhaps I need to be going down this route? Netgear DM200 - OpenWrt does not support G.993.2