iOS 15.1 Field Test mode, only getting intermittent data, old interface, where is signal strength number?

When I go into Field Test mode to ascertain signal strength, in iOS 15.1 on an iPhone 6 SE 1, by going to Phone and keying in *3001#12345#*, I only sporadically get data, perhaps one time in 10.

Also, I get what looks like an old interface. The screen does not have a dashboard like I see in some screen shots. The main problem is, I don't see anything called rsrp0 or rspr1, which is the number I am looking for.  When I go under "Serving Cell Measurements," there is a heading for "Average RSRP." Is this the signal strength number?

My partner's identical phone with iOS 14 behaves the same way.