My Gateway is offline since a couple of month because my project is no longer active.
The last firmware update i made was “dragino-lgw–v5.4.1675738086-squashfs-sysupgrade.bin” in February this year - and like you mentioned - the log in the router stays empty.
When my project was still running i always used the live data view from the things network website.
So unfortunately no updates from my side to this.
I am astonished that Dragino did not solve this problem until today. More than one year ago I had this problem (not showing anything in GatewayTraffic) with my Dragino LIG16. That is the reason why I still today use Semtech UDP.