15 Pro Max dropping frames on external storage

External Samsung T7 Shielded. Tested on desktop machine - drive consistently gets speed of over 950MB/s.

On the iPhone 15 Pro Max I can barely get 60fps on it. It drops frames CONSTANTLY when trying to record 4k 60.

I’ve tried all number of things, different formats, different cables, different recording apps, drive firmware.

The drive is clearly fine as it’s getting high speeds elsewhere, but the transfer speed on the iPhone, can’t transfer fast enough in order to actually film as stated.