First investment in Noida, but legal doubts are real

Did a site visit to Presidency Heights in Noida Extension last weekend. Honestly, the project looks decent, and my budget (around 1.5 Cr for a 3BHK) fits their offerings. But I'm investing, not just buying a home, so legal clarity is huge. My parents keep saying to check everything, but what does 'everything' even mean? I'm worried about title verification; heard many buyers skip this until it's too late. Also, MMR Group has a presence, but how do you *actually* verify a builder's legal track record before committing funds? And is RERA just on paper, or are complaints genuinely effective for possession delays or other issues? matlab, will it actually help if things go south?