I’m looking to update my home’s Wi-Fi system and was looking for advice on whether it’s worth replacing my router.  

First let me explain my setup:   I use both wired and Wi-Fi around the house.  My cable modem is located in my basement where my Ethernet hub is.  Unfortunately the basement spot is a very poor place to broadcast Wi-Fi from.  So I use a TP Link Archer C7 router with the Wi-Fi turned off as a wired router there as my DHCP server (I hope that’s the right term) and then have two older Wi-Fi extenders that I have set up as wired access points upstairs at opposite ends of my house.

I’m planning on updating my wifi with Deco X55 units.   Two of these should give me adequate Wi-Fi coverage and I plan on using wired Ethernet connections on these replacing the older extender units as AP’s.

So here is my question:   Should I also get a third x55 unit to replace my older Archer c7 router that’s around 9 years old?   Since it would be in the basement I don’t see it contributing much to the waif coverage but I was wondering if the newer routing/DHCP server would offer any benefit over the older C7 router and/or having all X55's would offer other benefits?  

If it’s relevant, I have Comcast cable with speeds of about 400 mbps down and 10 up.   I don’t game and have fairly basic household/home needs.