Hello, my question is:
Moved to Germany this year. I got my bluecard for 7 months, and recently quit my german job. I plan to work remotely for a company in Asia. Money is not an issue, and I dont need unemployment benefits.
From different people I heard that I should just ignore ABH, dont report anything there, because I got a blucard where it says that it is valid for 4 years.
So, will I have any problems if I just ignore ABH living my life and working remotely? Not having any contract with German company?

As a Blue Card owner you are required to notify ABH (esp. in the first 2 years) about any change in your employment plan/salary/location. As blue card is solely a qualified worker's permission, no job means no right to hold a blue card. That being said, it doesn't mean that you need to leave Germany immediately, they can give you some time to find a new job etc. depending on your circumstances.

I don't know at all what happens if you don't tell ABH. But if you don't and they find out themselves, it doesn't seem unlikely to me that they make you leave immediately and never allow you back. I'm not a lawyer or anything so what I'm saying may be wrong, but I wouldn't risk it to be honest.