Hi, I have two Archer C7s acting as WDS clients to create two wireless bridges to the main router R7800. These are hub and spoke topography, not daisy chained. They are set up as detailed here: https://openwrt.org/docs/guide-user/network/wifi/atheroswds
If I want to move the WAN connection from the R7800 to one of the Archer C7s, do I need to change the config of the Archer C7?
The WDS configuration would stay the same, but the overall network changes. Clients need to know the IP of the one which is connected to the Internet as the gateway. This is generally done by making it the DHCP server and not running a DHCP server on the other ones.
Also it's conventional for the gateway to have a .1 IP address but this is not required.
Note that a C7 has a lot less CPU power than the 7800 so if your ISP speed is > 100 Mb you should use the 7800 as the main router.
For 3 or more APs, using 802.11s mesh may be a better idea.
My set up is r7800 - c7(1) - c7(2). A wireless connection is possible but weak between r7800 and c7(2). I have no need for wireless roaming of clients across the APs.