Premiere Rush Poor very quality

Ok, so my YouTube videos have been poor quality so I've been testing to see why... Tested the cameras and they were fine. I've realised the issue is when exporting -

I use an iPhone 12 Pro Max in 4K 60fps to film

I then add footage to Premiere Rush

Create video using footage

Export footage in 4K Match frame rate

Once the video is "Ready to share" the image looks fine in the preview window, however when I view the video in my Photos app on the iPad Pro the image is not as good with lots of colour loss (compared to the original footage)

please help, I enjoyed using PR but I will be cancelling my subscription immediately unless this can be resolved, thank you.

I have attached 2 images, the preview window... and the a screenshot off the downloaded footage... look at the colour difference