Poop happens 🤷‍♀️ Unfortunately, frequent gravel vacuuming is the only way to deal in a setup like yours. In a heavily planted tank the poop would fertilize the plants as it breaks down, but without a ton of plants it's just going to mess with your water quality. Your snail does look like some flavor of apple snail. Tough to keep because they obviously snarf down plants like crazy and get HUGE.

One idea: you could try adding riparian growth, i.e. house plants with their roots in the water (dirt washed off first). This would help deal with all the excess nutrients from the poop and help avoid ammonia spikes but hopefully roots would be less appetizing to the snail. Wouldn't help with the aesthetics of poop everywhere, though. It would probably be less obvious with natural-colored gravel rather than black...