I'm assuming the Fiat 500X chassis was never designed for off-road. If Jeep didn't modify it to make it stronger, perhaps it's just not rugged enough to take a beating on rough washboard.
It's not quite like that. Take 5 mins to look at this Wikipedia article.
Although the Renegade probably shares a lot of the lower part of the bodyshell, along with engines, suspension, etc, it is still a different body shape. It's certainly taller and may well be 'more rugged' than the 500X. Bear in mind that the 500X also comes in 4x4 option, though possibly not to TH standard, so the platform may have included some off-road design points.
The matter of taking a beating from your use falls into two categories. First is a yes/no ... Does it have the ground clearance, etc, (with some mods) to physically fit down your routes? The other aspects really are a question of how long parts will last, like shock absorbers. That's hard to say until the model has racked up years of experience, which with only 2 years in production so far is a little way off.
Previously: 2017, 1.4 petrol, 6 speed auto, FWD, Limited, Omaha Orange ...
Now gone electric.