How is "de" used in Chinese adjectives?

First, I need to say, I am an English learner. So, you need to endure
my poor English writing.
Ok, back to the context.
1.Sentence which has Chinese pronunciation as follows:
“geng duo de dan gao” is totally equal with “geng duo dan gao”.
I don’t know anything about Chinese grammar. Even more, I am amazed to know that Chinese like English also has grammar.
My recognition is:
de” is mostly required to use before something, when it belongs to something else.
Beacuse“dan gao”is a noun, which doesn’t belong to an adjective of “geng duo”, so basically it is not needed to put“de” after the“geng duo(很多).
In some instances, like “the book belongs to him”, In English we say
“his book”. In Chinese we say 他(he)的(di)書(book). If you miss the ”di” in this sentence, then, it make no sense.
2.In situations, if we don’t put “di” between two word(phrase),
sometimes make phrase obscure, then we normally use “di”.
For example: “This is a big flower”. If we just character-by-character
translate this small sentence, it would be “這(this)是(is)一朵(a)大(big)花(flower)”.For example in a situation, if you’re showing a flower to your customer, the phrase of “這是一朵大花”make sense. But if you’re delivering a speech, no one knows there will be a word of “花(flower) in your speech, then the meaning of ”大花(big flower)”will be obscure. Because you know, sometimes “大花 has other meaning, for example a dog’s name, as we often use“big”or“small”for animal’s first-word-name. So, for the purpose of making the meaning clearly to add “di” in this scenario is needed.
3. What Alud Lang Syne says is right, there must be many
exceptions. Because I don’t even know Chinese has grammar too.

if the adjective is made of one sinogram, then 'de' is not necessary , but if the adjective has two sinograms, you must use it
beside that, there are some exceptions