The car best suited to your needs is the Mahindra Thar Roxx. It's spacious for five and has a 5-star Bharat NCAP crash test rating, and includes ADAS with Level 2 Autonomous driving, which could come in handy on your highway drives. Most importantly, it is a tough, ladder-frame SUV with robust suspension that is very well suited to rough roads and off-road driving, even if you choose the 4x2 version.
However, an automatic version will stretch the limits of your Rs 16.5 lakh on road budget, and you might have to spend a bit more to get more features.
Additionally, if you can wait a bit, the new Renault Duster is going to be launched in India on January 26, 2026, which promises to have the same tough construction as the previous version, and is likely to have a price tag lower than the Thar Roxx. It might be worth the wait.