Sea traffic is pretty muc non-existent in the base sim, whatever platform you’re on. On PC there are mods that fix that. From what I hear, the payware global shipping mod is coming to the marketplace, so that will likely be available on Xbox as well.
As for air traffic, that’s another one of these issues that seems to be hit or miss on a person by person basis. After rarely seeing another plane in the sky for months and months, the I’ve had tons of air traffic the last 3-4 months or so. Some parts of the world have far less (Europe has surprisingly little), but where I fly in North America, the skies seem quite busy. Nowhere near as busy as they are IRL (10-20% of real world traffic at best), but at least I’m seeing planes now.
But yet there are people on both platforms still complaining they’re not seeing any air traffic, so this isn’t a console specific thing. I don’t know what the cause of the problem is. I suspect it’s something on Microsoft’s end on the servers you connect to in order to get your traffic (or lack thereof) information.
Like I always say, the most consistent thing about MSFS is how inconsistent the experience is from user to user.