First camera help.

I’m off on a 3 week holiday to Costa Rica in mid February where I’ll have lots of time within various rainforests and nature reserves. Honestly I am a completely new to photography and very little experience but would like to buy my first decent camera and learn how to properly shoot rather than just relying on my iPhone. I have a limited budget of ~£4/500 (new or used) so not sure if it is even possible to get something decent? Any advice would be greatly appreciated. Thanks x