I live in a relatively modern house (<15 years old) and the 5Ghz signal doesn't make it up the stairs. 5Ghz is 'same room' wifi, and I have Problems with it. It's the same with mobile 5G data, it needs so much more signal towers / transmitters to be effective.

I've hit 'forget' on my home 5Ghz network because it's just unstable upstairs, and my phone isn't smart enough to pick the network with the stronger signal for some reason.