Multiple diesel-automatic options will fall within your budget, but if you want a car as compact as the Maruti Suzuki Jimny. You could consider the new Hyundai Venue, which is well-equipped, and delivers good performance and efficiency. Albeit a bit pricey at the top-end, it feels like a well-rounded package.
Alternatively, you could also consider a mid-spec Kia Seltos, which shares its powertrain with the Venue. But will be a lot more spacious and will feel like a big upgrade over your Jimny.