Please excuse me if this has been discussed previously, but I was not able to find any discussions on this topic.

I have Verizon FiOS for my ISP and am using my own Archer C7 router with  dual-band WiFi. My current home network is a TP-Link PowerLine setup with both "dumb" and WiFi units (please don't laugh; I know it's old, but running in-wall cabling is not an option.) I would like to upgrade to a WiFi system and was considering the M5, S4, and AX3000 models, but all of these have instructions that say that one of the units would replace the router. I was wondering as to whether these models may be used in addition to rather than replacing the C7 in order to enlarge the WiFi network across three floors. Any information and/or suggestions from the Community would be greatly appreciated! GeneG