Your best options for sub-compact SUVs in your budget are the Tata Punch and the Nissan Magnite, both of which have received a 5-star NCAP crash test rating. Of the two, we recommend the Nissan Magnite, as it has recently received a facelift, which has given it more features and a more upmarket cabin. And overall, it is the more spacious of the two, and has the advantage of a turbo-petrol engine option, which also falls in your budget. As for whether you should buy a used car instead, it's always an advantage, as you will not suffer the same depreciation hit as you would buying a new car, and yes, you can get a vehicle from a segment or two above within the same budget.
Or else you could lower your budget and save some money. As long as you choose a relatively young used car and have it inspected thoroughly before purchase, the repairs should not be major in 6-12 months. Try a trusted used car portal like Spinny, which does thorough vehicle evaluation on its used cars for a bit more peace of mind. 
