So, an update from my side.
I seem to have the mesh working. I think.
Will need help confirming.
I took both my AX3 and WS5200 to my parents house today, and started testing. I found that my AX3 as secondary to their AX3 worked in mesh mode. Had it connected via cable and both routers seemed to be playing along.
Tested the WS5200 as secondary and... No go. Does not want to play ball. Also couldn't get their B618 to work. What I did notice is that it has a WPS button, not an 'H' button like the rest. So no mesh there. At this point I'm not sure what to make of the B618.
I ended up trading my WS5200 for my parents' AX3 and brought it home. That's when the trouble started... again.
With my AX3 as primary, I couldn't get the network up and running (not via cable at least). switched them around and again, routers refused to mesh. Then I tried mine as the secondary but connecting the two via Wifi instead of cable. This seemed to do the trick. I then moved my 2nd AX3 upstairs and plugged it into the switch- and it seems that it is still working, and reporting it's now connected via cable. At this point I'm not sure but I think I have it working.
Now, 1 thing I'm still concerned about. In a mesh setup, should I be able to distinguish between and be able to log into both primary and secondary routers? (Logging in via web, using IP addresses). Or should it only truly appear as a single router? Also, side note, Whole network is running on 10.0.0.x
When logging in to the 2nd AX3, I get this (shows repeater mode):
View attachment 1217876
The Huawei AI app also shows the following under the Hilink option tab, which it never did before (only showed one router with the 2nd being listed as a device o the first):
View attachment 1217882
As you can see, the secondary router shows it has my phone as a connected device.
View attachment 1217884
Also, even though both [AX3] routers report being on the same firmware, there is very definitely a difference- for one, my router has port forwarding settings under the LAN tab which the other AX3 does not have (when it was primary / used alone). The router I got from my parents has no port forwarding settings that I can find (for Plex, which seems to work anyway so no biggie).
At his point, cautiously optimistic things are working as they should. Or am I fooling myself?