Apple TV wifi outdoors

I have two ATVs, one is 4K, one is the prior model. I am setting up an outdoor movie watching rig, and brought the 1080p ATV outside to attach to the projector. It was working fine inside attached to a TV, but when I brought it out it wouldn't connect to wifi. I have an eero wifi system, so we have good signal strength and our phones and computers work fine in the same area outside.

I thought it was a problem with the ATV, since trying to forget and reconnect to the wifi caused the settings app to just spin without doing anything. After trying a number of times, I gave up and brought the 4K ATV out, figuring it wouldn't have the same issues. It behaved exactly the same, though. It couldn't connect reliably to the wifi, and trying to forget and reconnect to the network would cause settings to spin without doing anything.

So I brought one of the eero beacons out to the deck and plugged that in, figuring it would have much better signal strength being right next to the ATV. It seemed to make no difference. Again, I had my laptop and phone right there, and they had no issue with the network signal.

So what is it about the Apple TV that causes it to have so much trouble with a wifi connection outside? Is that the issue? It's the only factor that changed, so I don't know what else is causing it.