2015 Chevy Tahoe LTZ

I had 66 miles left till empty according to the guage. I drove 55 miles and my
car shut down while driving down the road. I pulled over just enough to get off
the road and restarted it, it chugged along 10 ft and was dead. I walked to the
gas station got a 2 gallon tank and proceed to fill the truck. When inside to
start it and the battery was dead. Flagged a friendly passerby to give me a
jump and the car would turn over but not start. I am wondering if the 2 gallons
wasnt enough to get it going or what the issue could be. Got the car towed
back to the repair shop and put another 10 gallons into the tank before
dropping it off. Came back with the wifes car to jump my vehicle and it couldnt
pull enough amps to turn over. Instead of getting a costly diagnostic done,
should I replace the battery or what other steps can I take to diagnose the
issue. The final time I tried to start it there was a distinct clicking sound
coming from the fuse box under the hood and the engine warning light was
illuminated. I did however hear the fuel pump kicking in the final times trying
to get it started. Really trying to avoid a costly repair here as the vehicle has
proven to be expensive to own, any help or tips is appreciated.