[Quoth]

It's direct (peer to peer) and you can't choose band or channel. I have never added my 15" Win10 laptop to any WiFi, it has no passwords. Yesterday was the first time WiFi was even enabled on it.
Because Miracast is WiFi and not adaptive for channel size and congestion the two ends ideally need to not be using WiFi for anything else. Also WiFi is a shared resource so if all the surrounding neighbours (and yourself) use WiFi for TV streaming, laptops, printers, scanners, tablets, security, cameras, phones, baby monitors, tablets, Set box extenders etc then Miracast will be jerky. It's a terrible system.

You can change the regular connection of WiFi on the laptop or Tablet to use 2.4 GHz or 5GHz (to WiFi Point/Router), but I see no settings for Miracast at either end. I've 3 Wifi points. One is dedicated in my son's bedroom for his phone & tablet. The other two appear on 2.4GHz and 5GHz as a single Airpoint and they communicate over 1GBps ethernet via the switch. They automatically chose which Wifi Airpoint and band a client connects to. They will change to narrower bandwidth on 2.4GHz (WiFi modes use 1, 3 or all the channels to get more speed, but sometimes one interference free channel is fastest). Most WiFi is simplex (take turns to TX or RX) and a single device at a time taking turns. MIIMO often is unusable due to neighbours or locations. There is a lot of hype both on Mobile 4G / 5G and on WiFi (version level).

Also I was looking at TV streaming for Tennis here and found that the TV HDMI streaming sticks all seem to be WiFi only and the boxes with ethernet don't support the service.

I can get over 500 Mbps on Wifi in view of the router and no-one else is using Wifi. But if I'm in another room and everyone is using it then the speed drops to 20 Mbps to 70 Mbps. The Ethernet cables go to a switch and can manage multiple streams to server, 500/50 Mps fibre broadband, peer to peer laptop to workstation, connection to secondary NAS etc. Even the Nintendo switch can use ethernet on its dock in HDTV mode or with a USB-C 3.0 ethernet adaptor (which also works on the TCL Nxtpaper11 without any additional adaptor. I have also USB-A 3.0 1Gbps ethernet, which allows the OTG adaptor with USB-C power feed.

Even with a direct cable a 14″ screen would only be use on a 13″ or smaller laptop.

Anyway, perversely miracast from Win10 to tablet in library was perfect, like a cable, but a noticeable increase in latency (affects local audio from laptop and mouse) and perfect in the lounge to TV, even streaming using Wifi on the tablet. Likely wasn't a very intensive web video, but ethernet could be used. A tennis app sub is available on Android, but she'd only watch on TV.