GT-AX11000 not happy in Wireless router mode

[japes]

Bare with me, this is a journey.

Hey all, I'm in Japan, and on a 1gbps line. About 8 months ago, I've had issues with packet loss and ping spikes while gaming on the wired connection, wireless was garbage too though. And over time it got worse and worse. Mostly at night, during busy times. I thought it was my ISP, but they checked everything and said the line was fine. OK, so I moved on to my hardware.

I was using a AX88U, I figured it went bad, so I upgraded to a AX11000. It didn't help. I did factory resets, went through every and all settings I could find. I really, really banged my head against the wall for months. I fought on the phone in Japanese with customer service, and finally, I signed a new contract with a new provider, though I'm still waiting for installation (it can take 3-6 months here, i know i know).

But then, this afternoon, I couldn't watch 4K youtube. I could barely watch 480p. So I started banging my head against the wall again. First I said frack it, let's get a baseline. I plugged my PC into the garbage router they provided me, which was directly into the modem. Suddenly everything is OK with my internet. Game ping is cut in half. 4K works. I'm baffled.
So I factory reset the AX11000 again, do the most basic setup, and start A/B testing it against the router from the ISP. ISP was fine, the AX11000 problems persisted.

In an act of shier desperation and wanting to know what could this possibly be, the only thing i could think of was to throw it into AP mode, and let the ISP modem do the driving, and let the AX11000 handle the wifi (I need the wifi6 or else I have dead zones in my home, the ISP router doesn't have it).
Well, in AP mode, everything was perfect. No issues whatsoever.

So it seems, I have 2 routers that are NOT happy in wireless router mode. TWO!

Let me map a map here to clarify.

1.
Modem - AX11000 (and previously AC88U) Wireless router mode - PC.
This has major issues, can't game, cant zoom, cant TV. But mostly a problem at night.

2.
Modem - ISP router - PC.
No issues

3.
Modem - GT-AX11000 AP mode - PC
No issues.

Can anyone shed some light on this?! I'm immensely confused. The whole "at night" thing really pointed towards an ISP issue, but I'm thinking it was just the traffic in my own house causing the issue. I also can't fathom why it would be an issue that degraded over time from a slight annoyance to I CAN"T DO ANYTHING ONLINE.


Save me jeebus. Thanks.

 

[Invisible Boy]

1) If it only happens at night, sounds like the typical cable internet issue where the bandwidth is shared among your neighbours.
2) It could also be WiFi interference because everyone is home at night.
3) Two dead routers in a row points to high ambient temperature that cooks the circuit boards slowly over time.
4) But then 2 problematic routers in a row can also mean incorrect settings.
5) Since your internet is fine with the ISP router, #1 is ruled out.
Maybe you can try to put the modem in bridge mode and let the ASUS router handles everything. Do a hard reset and see if it helps. You can also try the Merlin FW and see if the router overheats.