That's very low if it's the model with the integrated Intel GPU, but entirely reasonable if it's the one with the RTX 4060 GPU. Just as you can buy a Ford Mustang with a 4 cylinder Ecoboost (20-30 mpg), you can also buy it as the V8 GT500, which gets about 12-15 mpg.  Same car, different engine.   You're not going to get good battery runs out of any system designed for high performance video any more than you get good fuel economy from a sports car with a big twin-turbo  V8.  
I just got this for university and my laptop only gets 3.5 hours of battery life. Is this normal? It doesn't seem acceptable for a 2023 laptop to run for only an eighth of a day. 
Inspiron 16 Plus 7630, 3.5 hours of battery life?