Export iPhone 12 Pro+ Video HEVC

Hello - I have seen numerious threads on this topic, and all involve some convuluted approach rendering to extremely large unusable formats.

Someone please tell me...

How can I export iPhone 12 Pro HEVC footage in... HEVC - the very same codec that the iPhone uses natively?

Premiere imports it fine

Premiere previews it fine

Premiere exports it and the colors are all washed out.

Here's my workflow:

Import raw footage from iPhone (.MOV format)

Drag into timeline to create new sequence

Add WAV file of music

Mute embedded video audio track

Trim video to align with start/end of new audio track

export

That's it! No fancy cuts - no transitions

We're talking music over a track!

What I've tried:

Tried changing the HEVC tier/profile to High/Main 10 - which allows me to update the  export color primaries... except then I can not use hardware encoding, and software encoding immediately fails.

NVIDIA supports it - premiere does not.

Tried exporting to a different format

Took forever - file size was huge, and end file was unusuable by YouTube.

What's even more confusing is I literally had this working a few weeks ago

I exported this video HEVC Tier Main, CBR 40 kbps

https://www.youtube.com/watch?v=5UmorKkZYTM&feature=youtu.be

Updated Premiere to latest version yesterday, and now my videos look like this:

original clip looks like this:

What is going on here?