I have a 2016 Chevy Tahoe LT, when I turn the key to start it, it hesitates, but eventually starts a few seconds later. What's this, should I be worried?

Use your warranty.

Your explanation describes a common problem, which is low overnight fuel pressure. Have someone perform a fuel pressure leak- down test, which can also occur once the vehicle is shut down for several hours if you have a faulty fuel pressure regulator or sooner if your regulator has failed. Only a fuel pressure leak-down test will rule out the regulator as the cause, then, it's down to the fuel pump. When was the last fuel filter service?