Issues trying to compare cell dBm between carriers in my area

In the process of buying a new cell phone and trying to determine which cell provider has the best LTE signal in my area. I'm currently using Spectrum (Verizon backbone), while my wife uses AT&T. When checking the rsrp data for my wife's phone, she's receiving -123dBM and an rsrq of -13. When I look for the same data on my Spectrum phone (iPhone XR), I can only find an rscp reading of -14.

Is there a reason Spectrum / Verizon doesn't appear to provide an rsrp reading for my phone, and is there another reading I can use to compare cell signals between companies?