The RT-AC3200 theoretically should be able to handle the 940Mb speed you would get as it has a 1Gb WAN port and the LAN ports are 1Gb, however as devices are also added to the device, the bandwidth may have to be divided if for instance multiple devices are accessing that bandwidth at once. That router is still a decent router, as I have the RT-AC3100 version with minor differences.
Now going to a more powerful router, does net you a faster processor that can coupe with the extra load from those devices, and when it comes to WIFI, has better handling. The network card and ports can also sometimes be slightly higher end variants, but that is also part of what separates the more expensive routers from the less expensive ones. Yes most of them get classified as gaming routers, and part of that is due to extra features for controlling traffic, and making the gaming experience better, but you also get a device that can handle a larger volume of devices simultaneously with ease and last longer. Even if you go with a higher end router, there may be other factors also involved that can keep you from achieving the full bandwidth of the network.
One last option may to build a custom router running something like OpnSense or PfSense and have more flexibility in the long run and use hardware that can achieve that speed and then some. Options are wide and available. Just a decision of what price you are looking to cap at and how you want to achieve that optimal performance.
