Sorry All Sifu i got a noob newbie question
Currently im using old TM unifi huawei modem+ Asus router for 500mbps plan
New 1gbps plan come with brand new single device combo (modem+router)
do we required to change that to enjoy higher speed ??
can i still keep using my old TM modem + asus router setup ?
if no , is there any guide to set the new tplink ONU to be able to link with my old asus router ?
any help are appreciated !

Are you already using new ONR?

If so, go to Setup > Ethernet WAN > Connection_0 - Edit > PPPoE drop down change to bridge > to whichever router you want (From ETH port 1 to another router WAN)

You’ll turn the ONR into basically ONU again, it’s just handling VLAN segregation from TM (209,400,500) and ATA (VoIP), you can also leave the 5GHz WiFi band turned on so that you can connect to the WiFi to configure whenever when needed and no need to use any LAN cable

I’d find my post of screenshots but should be quite easily understandable

Also a reminder that doing this will limit your top speed to 940mbps due to TCP/IP transport overhead due to the presence of 1G port instead of 2.5G, so you won’t get the up to 1030Mbps limit of DL speed if you’re on 1Gbps plan and was expecting that