If you got it from a store, then maybe it's worth exchanging it for the same one?
I have the PG348Q. It's a 3440x1440 IPS @100Hz 21:9 monitor. Though it is not HDR. I'm super happy with it. It lists for US $1,000. They announced a HDR version with I think 200HZ capability. But no ETA on it's release.
For posting videos from your iPhone, you could upload it to YouTube. Then link your YT video in these forums.