I've never studied it but I'm familiar with the basics and from what I've read and watched online, I've gotten the impression that German is a language where rules don't help too much and you just have to memorize everything. You can't tell the gender of most nouns by looking at their ending like you can with Spanish or Russian, so you have to memorize it with the article. I've heard there's many irregular plurals too. And also a high number of irregular verbs.

Is my understanding correct? Is German a memorization language? Or will rules help you a decent amount?

Thank you!