Oh honey, I've been there. Three weeks of zero spend makes you want to throw your laptop out the window.
First thing first - Google's quality score is probably lying to you, but check it anyway. If your keywords are generic garbage or your landing page is a glorified brochure, the algorithm will starve you. Targeting too broad? Same problem.
I spent months tearing my hair out over this until I realised most ad platforms just hate guessing. You need to know what people are actually saying before you throw money at keywords. That's where I started lurking in the wild corners of the internet to steal their language - worked better than any dashboard.
Don't just blame the platform; blame your strategy.