Redbellies are only aggressive if threatened, unlike the browns that gets territorial and will go you. Redbellies aren’t lethal as far as I know, but they’ll mess up the body bad, especially a kid; necrosis from clotting, nerve damage, huge swelling, etc. Also definitely depends on the bite. Used to be friends with a snake handler who got bit by a coastal taipan and got anti-venom within the hour, but ended up being a dry bite (or mostly) anyway.

The one I hit with the mallet had just been knicked by the neighbour’s chainsaw cutting up the log out of a huge fallen tree. I had the mallet because I was doing my kid best to hit steel wedges in to help split the wood off. Suddenly, very pissed off snake going toward me fast.