Color Management Troubles

First, I am fairly new to Resolve, so bear with me. My exported videos are not matching what I see in Resolve.

I have a project with Color Management settings of:

Color Science: Davinci YRGB Color Managed
Resolve Color Management Preset: Davinci Wide Gamut
Output Color space: Rec709 2.4

I have started grading a long project and just noticed that my exported renders are wildly off from what I see in Resolve. I am using OS X 11.4 on a 2016 iMac.

I have made a video that shows everything to make it easier to see the issue.

Thanks for any help!

Read these:

"Grading for Mixed Delivery: Cinema, Home, and Every Screen in Between" by Cullen Kelly
https://blog.frame.io/2019/10/14/gradin ... -delivery/

"How to Deal with Levels: Full vs. Video" by Dan Swierenga
https://www.thepostprocess.com/2019/09/ ... l-vs-video

and
"A Deeper Look at Consistent Color with QuickTime Tags From Resolve To YouTube & Vimeo on Wide Gamut Apple Monitors" by Dan Swierenga
https://www.thepostprocess.com/2020/07/ ... ktime-tags

and I think they cover the issues and the solutions very well. Understanding color management is also helpful:

"Color Management for Video Editors"
https://jonnyelwyn.co.uk/film-and-video ... o-editors/

My simple method: always export a second or two of SMPTE color bars at the very head of the project, and then check them on scopes in whatever player you're using to see how it looks. If there's a shift (video level or hue or chroma), you'll see it very quickly in bars.

Note that the same image will look different on different browsers, different operating systems, different laptops, and different desktop displays. It's even worse when the displays are not calibrated. Sound has similar issues.

The short answer is that how you view the image matters.

The only 'correct' way is from a hardware player to a calibrated display.

That means you need to add a Decklink while in Resolve, and get the export off the computer afterwards.

This is all great info and I will definitely read/watch it all, but do any of these resources explain why the exact same clips with the exact same project color management settings export dramatically differently from different projects? That's my real problem (shown in the video).

My test project uses the same clips as my source project, with same project color management settings, yet exports different results.

Thanks for the info.