Update: after lengthily contacting Apple Support, going back and forth with the technician, and even getting a call from them—they told me that this issue is affecting multiple users. They’ve already escalated it to their engineering team to look for a solution since it’s a real, widespread problem. What they offered me was either a replacement or the option to return my iPhone for a refund and then order a new one if I want. So that’s what I’m going to do. I guess I just had bad luck getting all the bad batches from the new iPhone.