Celluar hotspot data

Questions
1

Around half a month ago I made a similar thread asking, I’d just like to know, even though the cellular provider may know who I am, by using mullvad with a kill switch, would they be able to see any of the traffic of my device? I’d assume the VPN covers general wifi tracking but what exactly do cellular towers collect on you in terms of data? And does that breach privacy? (Other than of course them knowing my location through triangulation though there isn’t much that can be done about that from what I’m aware).