Flickering Exported movies

Hi,

I am getting a lot of flicker and glitches in exported movies.film was shot at 24 fps using cinemativ mode on Iphine 17 Pro max and edited omn same phone. I have tried exporting at different qualities and frame rates but flickering persists. I have closed down all other appas a point of export, but movies (6) are all unusable

I save to files on phone and use icloud desktop to transfer to PC to upload to Hootsuire.