Australia is a dangerous place, have you been in the military? Maybe get training before you visit
Yeah, watch out for the drop bears. I've lived here since 1966. I've seen a snake in the wild once. I've never seen a shark in the water, or a crocodile for that matter. Only the cops carry guns and we've not had a mass shooting since 1996. We have one of the lowest COVID death rates in the world.
The greatest safety precaution you can take is to learn to swim. Drowning is the leading cause of death for tourists. Australia is a huge place, nearly the size of the USA if you exclude Alaska. There are plenty of dangerous places, just like the US. Do your research.
Australia is a federation. Each state is different. The North is tropical; it can snow in the south.
What we don't have is the level of violence and gun crime that some areas of the US and UK experience. Sorry, UK is more knife crime. People are just as dead as if they were shot. Population density is low, except for the cities where most people live. The Crocodile Dundee image is nothing like the reality for the vast percentage of the population. No one sends their kids to school wondering if they will come home alive.
My parents took me overseas just before my 13th birthday. I am exceedingly grateful. I love the English countryside. The "dark, satanic mills" have been replaced by wind turbines and minarets. London, aka Londonistan, is far from safe. The Muslim mayor tells people terrorism is just part of life now. Christians have been arrested for preaching on the streets.
I'm not sure what kind of training equips people for living in England now. Learning Arabic might come in handy.