Compond Clip acts weird when copied to a new timeline

I am working in the edit page

Doing a rolling credits and I am placing BTS clips off to the side with rounded corners and reduced in size. Most of the clips are Arri Open Gate 4448 x 3096 but some clips are 4K iPhones footage.

I created one Arri clip with all my settings and then just pasted those settings on to all the other Arri clips

So far so good.

Then I wanted to do the same with the different sized iPhones clips.
I changed the iPhone timeline size to the arri timeline size
then made the clips I wanted to use into Compound Clips.
Thinking ok, these compound clips are now just going to react the same as far as resolve is concerned as the Arri clips of the same size.

But they don't
They squish and stretch and crop weird when I bring them into my other timeline

Do Resolve "Compound Clips" not just "precompose footage" like in After Effects?

To fix resolution problems in a compound clip, right-click the clip and select "Open in Timeline." In the Inspector panel, under the Scaling section, you can adjust how clips with different resolutions are handled: choose "Crop," "Fill," "Fit," or "Stretch," depending on the desired effect. This usually solves the issue. You can also reposition clips using the Transform and Zoom controls, both within the compound clip's timeline and on the main timeline.

Remember that when copying and pasting clip attributes to a compound clip, the attributes affect the compound clip itself, not the individual clips inside. Therefore, avoid using compound clips if you want to apply attributes to the inner clips. Unless you are content with going trough the hassle of doing it by opening the comound clips in its own timeline and doing it there. I don't think you want to be doing that. There are better ways. While trading flexibility for easier conforming can be useful, it's generally better for later stages of your workflow.

Do Resolve "Compound Clips" not just "precompose footage" like in After Effects?

They are not the same. In Adobe, precomping is often the only way to accomplish many tasks. In Resolve, it's generally best to avoid precomping unless specifically needed, as it can limit flexibility.

Using compound clips trades flexibility for conformity. Unless conformity is your goal and you're willing to sacrifice flexibility, avoid using compound clips or similar precomping methods. There are usually better alternatives.

Compound clips, Fusion clips, and multi-cam clips are essentially nested timelines with a protective container and unique features specific to each type.

Compound clips are a form of nested timeline. Editing a compound clip is like editing any other clip: you can edit, trim, and delete them using the same methods. You can also rename compound clips and decompose them back into their original clips within the Timeline. Decomposing restores the original clips, but discards any adjustments made to the compound clip container.

When you create a compound clip, it replaces the selected clips in the Timeline. A copy of the compound clip is also placed in the currently selected Media Pool bin. This allows Fusion to access it, as Fusion uses clips from the Media Pool. Opening a compound or Fusion clip from the Timeline sources it from the Media Pool, requiring a duplicate.

However, dragging and dropping that compound clip to a new timeline treats it like a separate clip, not the original compound clip. Even if you decompose it, the copy remains.

You can open these nested timelines as independent timelines and perform most timeline operations within them. Right-click a compound clip and select "Open in Timeline." The Timeline updates with the compound clip's contents, which you can re-edit.

Because compound clips act as a single clip in the Timeline, they appear as a single MediaIn node in the Fusion page and can be graded as a single clip in the Color page. To individually apply effects, adjust RAW camera settings, or grade the original clips within the compound clip, use "Open in Timeline" to access the original clips. Then, open the Fusion or Color pages, where you can composite or grade each individual clip separately. When finished, return to the Edit page and close the compound clip to revert to viewing it as a single clip in Fusion and Color pages.

Additionally, you can apply different options to each clip inside the compound clip timeline using mismatch resolution options, located in the Inspector's scaling and retiming section. You can choose "fit," "fill," "crop," or "stretch."

Generally, using compound clips seems unnecessary for your described workflow. Copying and pasting attributes can work, but potential issues with different aspect ratios (like horizontal vs. vertical) may arise. In that case, you'll need to decide how to fit them.

The "Input and Output Sizing" section of the reference manual describes settings that provide most of what you need. For complex multi-aspect ratio animated scenes, consider using Fusion, which offers more control and tools for these tasks.

"Remember that when copying and pasting clip attributes to a compound clip, the attributes affect the compound clip itself, not the individual clips inside."

Yes. Yes. Yes THIS IS WHAT I WANT FROM A COMPOUND CLIP!

The solution seems to be to just render out the iPhone clips at the resolution of the larger clips (actual size) and bring them into the timeline and easily copy the settings over to the modified and saved out iPhone clips. NOW they act as I would prefer a compound clip to act.