Following options should be available in this budget (Pakwheels and Olx prices are overstated).
Each has its own pros and cons that can be discussed for hours.
Suzuki Jimny 1998-2010 - easiest to maintain and run but will have to compromise on comfort and space. A capable off-roader.
Toyota Surf 1993-95 - easy to maintain but will require time, money and energy to bring it full reliability and liking. Aged vehicle but latest amnesty imported ones might be better option.
Toyota Land Cruiser 70 - Basic vehicle and hence easy to maintain and run. Capable Off-roader. On road limitations. Aged vehicles. Avoid the ones with altered engines.
Toyota Land Cruiser 60 - Basic vehicle and hence easy to maintain and run. Capable Off-roader. On road limitations. Aged vehicles. Loads of space.
Toyota Prado/Land Cruiser II 1990-95 (highly overpriced online but serious sellers sell around between 20-30) - capable on and offroad - will require time, money and energy to bring it full reliability and liking - 7 seater and official Taxi of many northern areas. Aged vehicle.
These 2 videos might also be helpful, one of the channel has detailed review videos of SUV used in Pakistan market