Upgrading to a 3BHK: RERA worries are real

Visited a few 3BHKs in Noida Extension and Sector 150 last weekend, and honestly, the price jump from my current 2BHK in Sector 78 feels huge. I'm seriously considering an upgrade, maybe a ₹1.5 Cr budget, but the legal side scares me. How effective are RERA complaints, really? If a builder like Unnati Fortune Group delays a project, what are my actual legal options? I've heard stories, but is it just on paper? Also, when checking RERA registration for projects, what specific red flags should I look for beyond just the number? It's not just about the EMI, but protecting the investment. Any real-world experiences with RERA disputes here in Greater Noida would be super helpful.