@eplante Which FW release do you have on AX55 v1 and do you have its Smart Connect feature on ?

@christoskelton Get the ethernet cable from the AX6000 kit and use it to connect you computer to AX6000 LAN port. Any Cat 5E will suffice to connect AX6000 LAN port. Here's how to find your AX6000 IP...

@MikeB75 Both BE800 and BE550 support Easymesh ethernet backhaul - details. Your BE550 should be in wireless router mode (factory reset) to configure this - here's a guide.

@christoskelton Post your network status screenshot: along with its ethernet port status:

@eplante Did you try the High Speed mode in RE605X Advanced setting - details.

@Sabhanam In order to be able to connect all your 4 PCs to each other, you have to configure one of the Archer C6 in AP mode (Case 1) so they can be in the same subnet.