Videos taking forever to load, even when they were just filmed.

I have the new iPhone 16 pro max and whenever I take a video (even if it is only 30 seconds long)when I go and try to watch it back, it takes a really long time to load. Similar to when you are restoring videos from iCloud. The video goes starts jumping and glitching. A 1 minute video can take up to 5 minutes to load! Why is that when I just took the video 30 seconds beforehand? It's really frustrating because I'm on the fastest network in Australia with the best coverage. And I didnt think using the camera would need to use data.