Is it possible to suppress Missing Prefab errors in Unity 2021?

My own prefab is referencing prefabs of an external paid asset.

If I do not import the external assets, I get the following Missing Prefab error:

Problem detected while importing the Prefab file: 'Assets/XXXX.prefab'.
The file might be corrupt or have missing nested Prefabs.
Errors:
 Prefab instance problem: YYYYY (Missing Prefab with guid: aaaaabbbbbcccccccdddddeeeee)

The error disappears after importing the external asset.
However, the error also occurs when playing a scene that does not require the external asset.
I have multiple scenes in my Unity project and I am using Unity as a simulator, not a game.

If I reference the prefab of the external asset directly in the scene without creating my own prefab, the error will not occur when start the Unity editor, but only when open the scene.

However, this would require the creation of similar objects in each of the multiple scenes. This would result in multiple management of the same object, which I would like to avoid.

This Unity project is available on GitHub.
I want to be able to play some scenes by those who do not have external assets.
I did not get this error in Unity 2020.

Please let me know if you have any good ideas.
Thank you.

The official response was that this behavior is a specification.

Therefore, I will not create my own prefab that references external assets.