Google App Engine is probably best for your use case. It requires the least amount of infrastructure management, and allows you to focus on the application code. App Engine supports Node.js up to version 16 (as of April 2022). If you must use a newer version of Node, then consider another option.

Google Kubernetes Engine can certainly do what you need, but it can also do anything, and you have to have a significant level of expertise in containerizing applications and configuring Kubernetes just to get off the ground. I think Cloud Run is a better choice to compare against App Engine. If your application is already containerized, Cloud Run lets you just run containers, without knowing much about the underlying infrastructure. You can always migrate from Cloud Run to Kubernetes when needed.