Optimize storage on iphone. Viewing full resolution photos/videos from icloud.

So I contacted Apple regarding some questions of how to view full resolution photos/videos on devices after selecting optimize storage on my iphone 11 Pro. I know that the full resolution versions are stored in icloud, and compressed versions will be stored locally. They said I have to go to edit and then the full resolution photo/video will show up. However, they also said that if I shoot a 4k video on my iphone, that a full resolution or optimized version of that video will also be stored on the ipad. Does that sound right? I thought if you take a photo/video on the iphone, then you are just streaming it from icloud when viewing on a different device like an ipad.