2x ASUS RT-AX92U meshed routers connected to same internet source? HELP!

[Combat squirrel]

As title, this is abit of a strange use case but bare with me............

I will soon have 2x ASUS RT-AX92U - and I intend to mesh network them for greater coverage - but can it be meshed in an unusual way....?.

Currently 1 RT-AX92U is connected via its WAN port to the main internet source router/modem and works well - however this is connected via a LAN cable running between 2 buildings, the cable is underground and is 12-15 years old and has begun to rot I think as this LAN cable connection is becoming sketchy.

Building 1 = base router
Building 2 = RT-AX92U - A

Connected via underground LAN cable, building 1 & 2 have entirely separate networks by design.

My perfect plan if it's possible is - can 'RT-AX92U - B' be situated in building 1, connected to base router via WAN port, but be on Building 2's wifi network? (buildings around 20m apart, so wirelessly should reach in a direct line between the 2 RT-AX92U's.

The logic being - 'RT-AX92U - A' stays 'as is' - but when the LAN cable goes off line with its intermittent connection, 'RT-AX92U - B' also being a WAN connection to the base router can take over and feed internet data to the wifi network via its wireless connection until the intermittent LAN cable reconnects again?

Or is this not possible, and only 1 RT-AX92U can be WAN connected and the RT-AX92U - B can only be a wireless node?

If the latter is the only option I would have to make the wireless router be in building 1 only, disconnect the underground LAN cable and just transmit internet data wirelessly only - which is ok as my internet is only 70/20 speeds anyway, and I assume my local network inside building 2, on RT-AX92U would only use the strongest signal anyway for 'in network' wifi speeds?

Sorry to the essay, its an unusual setup!

 

[CrazyGreggy]

Can you attach a new Cat6 cable to the old one and pull it through?

 

[Combat squirrel]

Can you attach a new Cat6 cable to the old one and pull it through?

Very unlikely but I may attempt at some point, however I'll need to wait until summer I think to let the ground drain properly - I have a feeling the plastic pipe it was in has rotted and flooded.

There was 2 cat 5e cables in the tube originally, one failed and the other is beginning to go.

Funny story....the first one when I cut the plug off the end, water squirted out of it like a hose pipe for several seconds......astonishing it worked for so long lol

 

[Disco_P]

If I understand what you are saying then I don't think that would work, does your modem even have two ethernet ports?

I would wire in the AX92 in the same building as the modem and use it as the primary router, the second router connected to the first by dodgy LAN cable and in access point mode with wifi as a fallback?