I mean, you described it yourself. There's nothing else. Even if you had the budget for a more expensive stroller, the Inglesina and the Cybex strollers are not great for very very bad surfaces, so it would not be a good choice there. The Bexa prams are robust and feature large wheels, which is good for what you're describing, Still, as cheaper and simpler stroller systems, they, of course, have some disadvantages as they are bulky, heavy, and the seat is really simple, not that comfy. On the other hand, it is not the smallest, which is also good, and you'll get all the basic functions you need from your choice.
What I would maybe think of more with such bad terrain conditions would probably be a three-wheeler - or some kind of fixed wheel pram, as for really bad roads, three wheels or fixed wheels are simply better, even if they don't turn that comfortably. But these you'd have to order from somewhere, no trying it out beforehand (if it's not in your baby shops).
Still, you can lock your Bexa's wheels and work with what you have, given the circumstances. Calm down and enjoy your pregnancy, I wish you the best of luck 🤗