Samsung Galaxy S22 Ultra "Not Registered on Network" Error

My Samsung Galaxy S22 Ultra, still under warranty, suddenly started experiencing a network error. When I insert my SIM card into my friend's phone, there's a signal, but when I put it back in mine, there's none. I sent it for warranty service, and they returned it, claiming, "No issue found." Currently, my phone has no network, despite trying every possible solution, including a factory reset. I even tested with another SIM card, but the problem persists. A device I purchased with trust in the Samsung brand has become a source of regret. I need a solution to my problem.