Is Duolingo effective for learning German?

I started learning German on the Duolingo app, but I feel it’s not very time-efficient and wastes a lot of time. However, at the same time, I think it’s helpful because I started from zero. Do you have any recommendations or advice on this? Can you suggest any apps or methods for learning German effectively? Keep in mind that I can’t afford German courses and don’t have much time to dedicate to learning.