I lived in the South for a few years and never had any issues with bugs ir animals. I never saw a stingray or jellyfish in Florida, cockroaches were just normal sized cockroaches. The only two highly dangerous spider species in the US are the Brown Recluse and the Black Widow, both of which prefer to live in basements and can be treated easily in a hospital. Rattlesnakes and scorpions are native to the desert, and you won't see any unless you're literally walking there. In all honesty, I never saw any scorpions in my 6 years in the South, but I saw one just a week ago in the 10 minths of quarantine I've done in the Southern Cone.

I'd honestly say that heat stroke has a higher chance of ocurring and is more dangerous than some of the animals you'd find in the South, but to prevent any danger from the sun all you need is water, sunscreen, and a few towels for possible first aid.

I'd say that the dangers of the critters in the South are overexaggerated seeing as only very few are a legitimate threat and that the quality of US hospitals is much better than many other countries, so you'll be perfectly fine on the snall chance that something does happen.