Creating Mesh Network R7800 and AC1900

I am sure you can tell my intent by the title. I can create a network as an access point or range extender, but am trying to make it a mesh network. My understanding is this is the only option where seemless changing of nodes happens without the device having any connection loss. Currently I have to turn off and on the wifi when set as a repeater to change to the strongest node, or as an access point I have to switch to the other SSID. I have the 1900 connected via LAN, but it doesnt seem to pull from the LAN in repeater mode and again, as an access point it becomes a different network. Side note, these devices have a nighthawk s8000 between them but that doesnt seem to provide any other options that I can see. Thanks!