Yes, I am aware that there is more to agriculture, that's why I prefaced it and followed it up with my actual point, which is that this complexity pales in comparison to the complexity of any more 'engineered' processes.

And yes, agriculture may be fragile, but we're not gonna replace it anytime soon, because we need something that scales.
Reducing the amount of plants we need to grow by going for a plant-based diet is already a step in the right direction. I don't remember the exact numbers, but we might even be able to cut out Haber-Bosch.

In particular maybe also interesting for you is that legumes can help to reduce the need for fertilizer, because they fixate nitrogen into the ground. And well, plant-based diets involve a lot of legumes.
That's why they were often part of crop rotation and also the Three Sisters.