Terny has the correct answer here OP. While I have never used Docker in an enterprise environment (manufacturing applications aren’t known for supporting any technology from the last decade at least), I have used Docker extensively in my home lab. You don’t want to modify the container itself, but the image it was created from. The data doesn’t reside in the container itself anyway, but typically a volume attached to the container (assuming it stores anything in the first place). Your best bet will be to figure out what image the container was created from, and modify the image. From there, you can update the existing containers to use the new image, or move them elsewhere if you like.
You mentioned these VM’s are in the cloud. Depending on the hyperscaler, it is likely that you could migrate these to a native container service to save on cost since you wouldn’t have to pay for the overhead of a VM.