Please give your opinion on my parking options. :)

Unless the car is COVERED down to ground level, this is nonsense. Ground moisture IN THE OPEN has almost no effect compared to being on concrete/ asphault just a few feet away.

The only time open dirt/ ground has much effect is when it can evaporate moisture into the air INTO an ENCLOSED space, like a garage with a dirt floor. Especially if the garage is something like a non-insulated metal pole building, the combination of condensation on the cold metal at night, the re-evaporation in the sun, and the migration and evaporation INTO the garage from the ground can be very damaging.

I don't know what to suggest: Portable all metal carport? Use old sheets over car, and then a car cover over that? Again, don't tarp/ cover it down to ground level, let the underside be ventilated.