"a hard to detect bot" This isn't that much about the language used to code in. From what I read, most of digital fingerprints can be hidden/faked with almost any popular language using the right tools/modules and tweaks. What can be a roadblock sooner or later, is activity patterns, account authority and other social signals that happen inside the network.
Anyways, Python can get you up to a point, then you could combine it with other scripts/modules and then simulate some human-like patterns to stay under the radar.
* As I only know Python I can't give advice on - or make a comparison with other languages. Other members could enlighten us more.