I recently upgraded from a WiFi 5 router to a WiFi 7 one, and my bandwidth increase was a grand 0% (that's ok though I was actually just sick of my old router's shitty UI!)

There is about 10m and a brick wall between my AP and my desk so yeah, a fancy new MCS that can theoretically deliver 25Gbps was just never gonna be useful to me.

Also I've worked on (other non-WiFi) 802.11 products where our competitive edge was all about interference motivation. Our competitors at trade shows would see the demos and say "that's fake, you guys are cheating". So I have the feeling that in general there might be alpha in more resilient wireless links.

For your brick wall home situation; polarization duplex combined with some amount of beam forming/spatial-multiplexing plus importantly directional antennas on both sides of the wall would give you substantial gains even without increasing EIRP. Without EIRP increases it's the receiving side that needs the antenna to improve speed.

I saw a really good improvement through a floor for a device that has wifi 7 radio. Went from about 300mbps to 2000mbps. Going from 5Ghz 80Mhz channel to 6Ghz and 320Mhz was a big change. What has not worked with wifi 7 is MLO, openWRT doesn't really support it very well yet and neither did the original firmware but I have no one on 6ghz within range so its been stable and performant.

Powerline networking is worth trying for this too.

For a while I had wireless mesh networking in my new house, until I finally got around to pulling fiber to get a proper 10Gbps backbone. Upgrading from my UniFi WiFi6E AP to a WiFi 7 doubled my effective throughput as measured by SpeedTest. This in a 1930s house with solid brick construction.

How often do you see your router's UI to justify any change?