Sorry for the delay @michael.rosenberg. Not super familiar with the Glide feature set so I've been trying to learn more. As far as I can tell, the biggest difference between Glide and Retool is customizability. Glide might get you to an MVP quicker, but Retool lets you write custom Javascript anywhere, interface with pretty much any data source, and gives your granular control over when queries run and how to manage them.
We have a tutorial on our blog that walks through building an app on top of Google Sheets on our blog if that helps!