Can I use 5G service on my iPhone XR?

An iPhone XR does not support 5G. 4G and LTE only. It lacks the hardware for 5G.

click here ➜ iPhone XR - Technical Specifications - Apple Support

If you're using an iPhone XR like your stats say, it is not capable of 5G. You need an iPhone 12 or higher to use the 5G band.