I am lost. You want a running container that bases on a specific image to be updated real time?
Which part of it? The image? The container? The state of the application inside the container?
At least application state would make sense (~comparable to your google sheet example), though replication of application state is something that must be built-in into the application or service. Docker can only help you to run replicas, but will not take care of state replication, as it’s the responsibility of the application itself.
If you refer to the image than it would be like modifying a desktop app, and expecting that your change replaces the binary and all depending libraries on everyone else’s computer. If you refer to the container, you would expect the running process would be patched on everyone’s computer in real time, after the binary and depending libraries have been changes on everyone’s computer.