Gigabit ethernet and slow wifi speeds on AC88U

I just upgraded to Xfinity Gigabit. On an ethernet connection, I am easily pulling 800mb down and 41 up - what I would expect. However on my Pixel 5, standing right next to the router, I'm only getting 415 or so down. The pixel 5 has 2x2 antenna and a theoretical top speed of 866 down. I obviously don't expect to hit 866, but I should be able to get closer to that. Any specific settings I should be looking at?

Note all speeds are measured using speedtest.net in Chrome or the Android app.