Iphone 12 mini signal weak

my iphone 12 mini is horrible. My phone sits beside my daughters and wifes cell phones. They have the 7 and XR. Their phones have full service. My iphone 12 mini struggles to have 1 bar. I have had the sim card replaced. Ive taken it to Best Buy and they cant find anything wrong with the hardware. Is anyone else having this trouble with horrible signal strength. Its drops calls all the time and sometimes its showing it has full service when it does it. The absolute worst iPhone I've ever owned. May need an android after this.