Alexa, go home. Alexa, go to home screen, or something similar.
But since Amazon controls your home screen, it'll eventually show something else. Like Alexa For Your Day, sports scores that you never asked for, some advertisements, or whatever Amazon fancies for that day.
I used to love the idea of having a screen on my Echo devices. At one time, I've had eight Echo Show devices. But they've turned out to be a vehicle for Amazon to spam you with useless junk. Every few weeks they add some new "feature" to the home screen. You can turn it off through the settings, but a couple of things they won't let you turn off. I have three remaining Echo Show 5's. I'll be getting rid of them when they offer me a trade-in.