Question about TP-Link Deco M4 AC1200 Dualband WLAN Mesh 3-pack

Yes, this works with every router, simply switch off the WLAN at the router, the mesh system then takes over the WLAN and network function. The TP-Link M4 is not bad, but for almost the same price you also get a top modern WiFi 6 mesh system that can also manage up to 256 devices and provide a 3 x Gbit switch at each mesh router. Expandable up to 10 devices and equipped with the latest WPA3 technology and each mesh router has a 5 core processor built in. My recommendation:

Xiaomi Mesh System AX3000 (2-Pack)

Although there are now only 2 routers for mesh in it, they are much more powerful than those from TP-Link.

Yes, you can, connect the router to one of the tplink m4s with a power cable and deactivate wifi on the router.