I now walk in sandals. But my first 2 caminos were in shoes. They just lasted the distance, but were completely worn out, no tread, almost no cushioning by Santiago. I never took a spare pair, just flip flops for wandering around in evenings.
I would never wear boots, this is not a wilderness hike. A few people do, but remember for the most part you are walking on a path. And September is hot, early September can be really hot. The first time I walked it was high 30's, most people, me included , were having to come up with strategies for dealing with the heat. Lots of people traded in their boots for shoes in the bigger cities. I saw a beautiful pair of gorgeous hiking boots stuffed in a bin outside the outdoor shop in Leon. I knew they were super expensive, almost brand new, and even in my size, but walked right past.
There are definitely the shoe, sandal and boot camps. Finding out about sandals was the best thing.
I have the most difficult feet to fit of anyone I know, needing custom orthotics, and specific shoes/sandals. If I had a pair lost or stolen during the Camino the process to replace takes literally months and it would ruin my Camino. I take steps to ensure no-one can take or wear my shoes.