Some owners of the new, super-expensive Galaxy S10+ have taken to Reddit, as well as Samsung's own forums, to point out that their SIM-based functions are poor on certain carriers. A media outlet has tested the phone on this issue, and concluded that there may be some weight to the reports.
https://www.notebookcheck.net/Some-Samsung-Galaxy-S10-users-are-complaining-of-poor-cell-reception.415199.0.html