Best WiFi router for iMac?

There is no best in anything, whether it is a computer, house, software, car, etc...there are choices because we all have different needs. That being said I would recommend that you consider getting a Mesh Network. Personally I use the Google Mesh network. If you are unfamiliar with Mesh networks, please look up some articles on them to understand what they are compared to older non Mesh networks.

There are a lot of routers on the market of all brands sizes. I am kind of hooked on Netgear they have been in the Router business for sometime now. In fact I have a 2013 R7000 Netgear Night Hawk that is going strong still. What ever brand or model that you get I would recommended a WIFI 6 Standard for lasting power if you can afford it. Wifi 6 will not matter if you hook via a cat cable but your other devices right now might not support the Wifi 6 Standard but new ones in the future will and most Routers would be backward Compatible to other previous standards. You might want to go to Cnet.com and they usually have pretty good reviews on Computer Gear. And most standard will come with Cat Hookups and with at least a Gigabit Network connections.