Then arrange so the first one costs not too much, so if it fails you can try again until you fix it. Expect a less than 50% success rate to start with, despite your best efforts, and design your program around that so that it's not a disaster if the first attempt fails.
Then once you can do that - then send lots of them. And focus on sending innovative lightweight explorers to Mars.
And especially flying or balloon rovers may be worth exploring because they give you a chance to skip one of the most dangerous steps.Also - lightweight technology demo explorers on Mars. Well worth doing and would show to the world that they have done something interesting and are pioneers in space exploration.These types of rovers will also be useful for future telerobotic missions to Mars.I expect that eventually we will have humans in orbit around Mars exploring it by telerobotics. And will have maybe dozens of robots on the surface for them to control. If so - most likely international partnership perhaps involving all the major space faring countries to pay for it - it's an expensive mission costing surely many billions to develop. Perhaps something like the ISS around Mars.Then other countries then can join in by launching mini rovers to the surface of Mars for the astronauts in the international expedition to control.