Force Satellite To Specific Device

This is just speculation, but I'm wondering whether the issue is related to the channel(s) you're using. By default, the Orbi should be using both 2.4 GHz and 5 GHz. But, under the wireless setup page, you can choose the channel for both 2.4 GHz and 5 GHz. If you have the 2.4 GHz one set to "auto," and there's interference, the router and satellite might frequently be switching channels to find one with less interference, and a device connected to the satellite when the satellite changes channels might look first to the router, which is (hypothetically) still on the previous channel, even though it's farther away. You could manually choose a channel, and the Orbi won't bounce around from channel to channel anymore. If the devices aren't connected to the 2.4 GHz band, or it's not set to auto, then I don't know.

Also, this depends on the device, but you can sometimes, in the settings on a particular device, tell it to connect to a particular access point, by specifying an access point MAC address (or by blocking certain MACs). I have no idea whether an XBox has this feature, or your other devices, but if you can set them to ignore the satellite MAC, they'll be forced to connect to the router (or vice versa). As long as you don't rearrange locations (probably easy with the XBox, anyway), it should be fine.