I like the idea of incorporating rocks to spice up the design! But I think it’s too much for what the bridge meant for. I do carpentry projects as a hobby and I would never attempt to add a massive rock base to a simple footbridge. I say “simple” because it’s wood construction but simple doesn’t have to mean boring. Just like the cart isn’t boring imo.
Personally I find the bridges I posted to be very interesting and relevant to the style of the art. There were other options that were too basic and boring but these fit with the spirit of the art imo.
Again, I applaud your creativity and aim to build something impressive. I recommend going full wood construction.