Can’t locate signal strength.

I have an iPhone 12 and recently moved to the mountains. I was researching various cell signal boosters and read that you need to have a certain level of dbm/RSSI in order for some products to work. It was recommended that I try the field test by dialing *3001#12345#*

I followed all the instructions and was brought to the section on my iPhone that was supposed to show the RSSI (dbm) but it was not there. All of the other fields shown in the example were present except that one. Does anyone else have this issue? And can you tell me where I may find out my cell signal strength? Thanks.