My iPhone 16 Pro unexpectedly restarts. What can I do to fix this?

After the initail setup the phone keeps crashing, goes completely black like it has been turnt off then restarts itself. im not sure wether its related but im moving over from Samsung for the first time in around 8 years and noticed my photos that have been moved over are not syncing with iCloud. However it just seems to crash whenever it likes.

I am currently in the process of trying to reset it and start over but can't seem to make it that far.

[Re-Titled by Moderator]