@David-TP hi mate, it's  G634JY-NM040X. But I assumed all Scar strix 16 2023 model use the same WiFi card, which is WiFi 6E?

I don't have WiFi 6E compatible mobile devices unfortunately... probably thinking to buy an USB WiFi 6 to test... but before that, probably ask around first 

the service provider is Singtel..

any idea, mate?

  @David_2024 Hi David, i have the same issue and same router as well. HB810 is in fact the same hardware as the BE85 but looks like its re-branded for Singtel ISP by TP link.
I have issues with the 6GHz band as well and before i visit convergent for RMA i wanted to see if there is a firmware i can give a try to see if it can resolve the issue. 

My router HB810 is running 0.2.0_3.0.0_v6095.0_Build_231110_Rel.77341n which appears to be latest as reported by the Singtel website and the router while checking OTA from web console or the app. Issues im facing are, the 6GHz band will just disappear and if i haven't setup the 5Ghz on the device i am left with no connectivity. 
My setup, no band steering - 2.4Ghz separate SSID for my IOT (hidden) with medium transmit power). 5Ghz (WPA2/WPA3) with high transmit power. 6Ghz (WPA3) with high transmit power. My 6Ghz client devices, 1) iPhone 15 Pro Max (Wifi-6E), 2) Intel NUC 13 Pro, AX211 (Wifi-6E), 3) HP EliteBook 645 14 inch G10 - Realtek 8852CE WiFi 6E PCI-E NIC. So far i have no issues with 2.4GHz and 5GHz but out of the 3, 6E devices the iPhone is the most problematic as it is very sensitive and just wont see the 6GHz SSID most of the time. Then comes the NUC and lastly the HP laptop which works fine for a few hours until the 6GHz radio crashes and i have to reboot the router. 
What i have tried so far, 1) reset the router and setup form scratch at least 7-8 times (no backup restore of config). 2) Uploaded the same firmware file, just to ensure it wasn't a faulty flash. 3) tried playing with different setting - channel/width and even keeping the security to enhanced open (i know its stupid but just wanted to test). But nothing has helped. I am not sure mine is a faulty unit or its a firmware bug. Any help is appreciated, thank you in advance :)

  @DM_2024 mine is still not working until today 

  @David-TP thanks David! The release note doesn't mention anything positive but I will go ahead with the upgrade.

  @David-TP okay so here are some findings since upgraded to - 0.3.0_3.0.0_v6095.0_Build_240124_Rel.65899n. My Intel NUC with AX211 isnt able to see the 6G band at all. 15 Pro Max same issue nothing changed. HP EliteBook 645 with Realtek 8852CE issue persists, connects for a while and now 6G band is not visible.
Which means basically there was nothing addressed to either fix this issue or mine is just a faulty unit :(