Miyakojima Box Jellyfish!

I’m planning to visit Miyakojima in early to mid July and I’m a bit worried about jellyfish. How serious is it around that time?

Are there usually a lot of jellyfish in early/mid July (at regular beaches and while snorkeling)? I would love to do a lot of snorkeling while being there!

Are stings common? Is it more “just be careful” or “avoid swimming”?

Any specific beaches/areas that tend to be better or worse in July?

Thanks for any firsthand experiences or tips!