Actually, looks like I replaced that Asus AC66U router with Asus RT-AC1750 router, which I also got from you. It was almost 4 years ago, i.e. January 2019.
IIRC, you used to have an N66U, and I sold you an AC66U, which was branded AC1750, but was the AC66U hardware. That device with Asus' firmware on it, is now EOL and vulnerable to a cyber worm.
Either flash it with AC66U firmware from Fresh Tomato project (currently developed), or junk it and get a newer router.
This is the router that I currently recommend, that, or a Wifi 6 / AX router.
NVIDIA GeForce Now recommended wifi router for Steam, Uplay cloud gaming, console game, mobile game. Easy setup NAT open, wide range and smooth signal.
rog.asus.com
But that one can do 160Mhz channels, and is still getting updated.
It's currently $89.99 @ Newegg, on a sort-of clearance. Note that it is only good for Internet connections of 1Gbit/sec or lower. As Comcast/Xfinity and FIOS increase their internet speeds to 2Gbit/sec and higher, these routers will hit EOL effectively, if not literally. So if you are the type to subscribe to "max speed plan", these may not be for you.
The next best router, is the ROG Rapture GT-AX6000, which has both a 2.5gbe WAN and LAN port.
That one is around $300 on sale these days.
Yes, routers have gotten "fancier", and as a result, more expensive generation on generation. Of course, the WRT-54G was $159.99 when it was first released, too. (I bought a case of them for $11/ea. a while back. They do run Tomato and DD-WRT excellently, but are limited to around 36Mbit/sec.)