RERA: What they don't tell you about complaints

Budget finalised, loan pre-approved – now stuck on legal clarity for a South Delhi 3BHK. I work in real estate, but buying for myself is different. How effective are RERA complaints if a builder like Aarone Group delays? Those one-sided builder-buyer agreement clauses worry me. What's the best way to verify a builder's actual legal track record before signing anything?