The 5G phone with the best battery under ₹20,000 is the realme P4R 5G. It features a massive 8000mAh battery that lasts for over two days. If you prioritize fast charging, the OPPO K13 5G (80W) is a better choice, while the realme Narzo 90 5G (AMOLED) is ideal if you want a superior display.