very simple reason to avoid: mesh halves bandwidth.

You can see wifi as semi-half-duplex. You only have limited amount of concurrent talkers and that’s only with MU-MIMO (multi-user-MIMO). Most current devices support MU-MIMO on the Downlink side, but less talked part is that not neccessarily all of them support MU-MIMO on the Uplink side. And with mesh, there’s always someone upstreaming (either far side transmits or near side sends). Also, devices nowadays aren’t really idle, most of the devices are constantly sending/receiving, even if at low bitrate. With many devices that just creates unneccesary radio congestion. Multi-Point mesh is even worse, then you have multiple devices sharing the same radio channel and MIMO resources.

the only really usable meshing way is to have a dedicated radio backhaul just for interconnecting your access points and then have separate radios to serve clients. But, most home devices have just two radios. So either you backhaul with 2,4Ghz (much less total bandwidth, and many smart home devices like smartlamps, AC controllers etc still run 2,4G only) or you use faster 5Ghz as backhaul, but then stuck with slow 2,4GHz clients. Three radio devices are rare and expensive.

Mesh is cool for latency non-sensitive devices like smarthome stuff, low quality (or motion sensor based) surveillance cameras, regular web clients etc. As soon as you start to go into latency sensitive (online gaming, real-time communication), you’ll see bad (or occasionally bad and worst of all, uncontrollable) experience.

Do yourself a favour and use wired backhaul. If you don’t have enough cables, you can use something like Ubiquiti U6 In-wall AP (a very capable Wifi6 grade device and not that expensive), where you have an AP on the wall, but it has additional 4 port switch to connect your wired devices like consoles/PC-s/TV-s.

so you have your router (you can use your current one) and then run one U6 In-wall to each floor. That will take care of covering wireless services on that floor and you get to have 4 wired ports on each floor, so you can connect wired devices also.

Get a second R7500, install OpenWRT, and set up a mesh system a fair bit better than off the shelf.

You could could always get a Ubiquiti Dream Router and two U6 Lite APs for $400, then you have one AP per floor, direct wired, no mesh.

Otherwise, look at TP-Link Omada or Grandstream.

Not everyone needs fancy or complicated networks. If you want easy just go mesh with wired backhaul. The advantages are simple setup and having extra Ethernet ports at each node. The nodes also act like a switch so each one would give you the ability to connect more devices at that location. Yes OP could get really fancy but that doesn’t appear to be what they are after.

Flash the APs with OpenWRT. That’s what Unifi uses on theirs anyways. Disable wifi on the router or buy a dedicated one. Connect an AP in the basement via ethernet and one on the 2nd floor via ethernet.

https://openwrt.org/supported_devices

https://openwrt.org/supported_devices/432_warning

Plenty of tutorials/videos on different setup options, see which one works best for you.

YES… Asus routers support AI Mesh, and they will do what you need. Some of them even sell in pairs. If you have an older Asus router, you can add to the mesh. This is the pair I got.

Go to youtube and look up " tp link omada short stack" (router/controller/poe switch) . Add a couple 2 or 3 of their poe ap’s (eap610 or better) and you got yourself a nice prosumer set up! (Small learning curve to it)

Mesh term gets misused/mislead all the time… boils down to,

Mesh ap’s connect to each other wireless (with speedloss each step) but increase coverage. (Good for when things can’t be wired)

Ap’s connect wired to keep speed and increase coverage. (Best)

Both let you keep coverage and “roam”

Ubiquiti USG with a couple WAPs is the answer. I have a 3000sq dwelling with plaster walls. It’s glorious.

Consider buying something that supports openwrt. I currently use Asus RT-AX53U, it is cheap, wifi 6 compatible, and if you want you can use openwrt, which you can use to create a mesh, or just fast roaming access points. If you dont want to mess around with itj ust now, you can still use the asus aimesh. I had an existing mesh, but I wanted vlans for my iot devices, and I had to replace some of my devices.

802.11r was what I needed, which is fast roaming (thats what they call ethernet backhaul) Mesh is 802.11s. You might need both, but you can combine it

If you have wired backbone, you don’t need mesh.

Mesh is for people without wired interlinks.

Just put the same “migrate-able” SSID on all the access points on the same subnet. Your devices will eagerly migrate as you move around. You can tweak settings in access points (in OpenWRT) to make this happen smoother.

Additionally, you can add specific SSIDs to specific APs if you find “hoppy” zones. “hoppy” zones and devices happens when a device just migrates poorly and seems to end up on the worst possible AP it can be on. Usually the one without “kick on low ack” support. You can use specific SSIDs for those devices.

I have a lot of SSIDs and APs. I have even taken to hidding them just so I don’t flood the neighbours Wifi lists.

lan - house wide, all APs, all frequencies and channels

guest - house wide, all APs, all frequencies and channels

og5 = office guest 5g to force laptops to stay on the Linksys at near Gb speeds and not migrate to the hallway 5G.

o5 = office LAN (same reason)

ds24 = downstairs 2.4Ghz for the Shelly which is trying to have an affair with the AP in the garage, 3 brick walls away when there is a Nighthawk a 2m away!

dsg5 = downstairs guest 5g (used for work laptops only really, guests just use “guest”)

and so on and so forth.

Not all devices have access to all SSIDs. IoT and guest SSIDs are VLANed. etc. etc.

It requires support from multiple bridged virtual interfaces per radio, so you need a capable AP or one with OpenWRT installed.