2015 Enclave Leather.
Have you cleaned the connections on the battery lugs before battery replacement and checked all the connections between the battery and the starter solenoid? You may also want to check the voltage at the starter connection before, during and after the start cycle. I haven't read about very many starters going bad on these forums, only a few. I had an 08, eleven years old and 212k miles, never had a starter issue, but then every year has their one or two components which may arise to be problematic.