Ive got a gmc sierra, ill lock my keys in the truck and use the onstar app or mygmc app to unlock and/or start my truck from miles away. This is mainly while ice fishing or in the boat when i didnt want to risk losing the keys down the hole. I always have my phone with me in those situations, but i dont think this would be a convienient option for your situation.
You must have a pre 2018 truck or are you paying for the app? I loved that app for my 2015 and 2017 Silverados, but GM cheaped out and you cant use it for free starting in 2018 you had to sign up for Onstar. Pissed me off.