I'm a beginner in German as I only just started learning it more seriously this year despite loving the language my whole life. German compound words don't scare me that much as it's pretty similar to English compound words in a lot of ways, except that, in German, it's more of a hard-set rule while in English it's an evolution.
Or so I thought.
I've noticed that some words are actually not compounded even though I assumed they were. Here's an example. Chocolate milk is Schokoladenmilch. Oat milk is Hafermilch. But chocolate oat milk is Schokoladen-Hafermilch instead of just one word, Schokoladenhafermilch, which is very similar to how English uses dashes to combine multiple nouns into a kinda single word.
Is there actually a rule for joining nouns in German? And is it okay if I just assume that all nouns should be collapsed into a single compound word in writing, as in, people won't find it too weird? Perhaps it's like English in the sense that it takes a while for a compound word to come to be, making the language more descriptive than prescriptive.
Danke im Voraus!