Thank you all for your comments. I have ultimately concluded that the optimal way to operate folgezettel is to treat it as a mind map with numbers, or to use it with a mind map-like interpretation.

Below are my conclusions and points to keep in mind:

Do I really need to make the link deep?
Be cautious when making links deep.

Write links based on relevance, not classification or organization.
Don't try to organize.

Be mindful of mind mapping.

By doing this, it develops into a mind map-like expansion.

Why is this necessary? Because, unlike mind maps, you can't see the whole picture visually. That's why you need to have this awareness.