First international flight (18hrs), and first time leaving the USA. What should I even bring?

So my family(mom , dad, older brother) and I (22m)are going on a hunting trip to South Africa my parents won at a local auction. We leave end of the next month (April 2026)and i honestly have no idea what to pack for the plane. I was going to bring my PlayStation portal and hope the wifi on the plane is good but there’s no way it will be able to keep me distracted for the whole time. I need some more ideas but also don’t want to overpack.

Another thing is I am a huge snacker and drinker (not alcohol at all) so im anxious about what kind of snacks or drinks i would be allowed to bring on the plane? Can I bring my water bottle?If I buy it at the airport is it good to come on the plane?

I also have a large dependency on nicotine and always hit my vape. What would be some good alternatives for that while on the plane/vacation?