lower the difficulty- higher difficulty speeds up the timescale (and thus reduces the story playtime so it's kinda punishing play in general imo), makes you starve and tire faster, but also gives bigger dailies and thus more bonus pay (but it's also way easier to screw up hashes and make no bonus), whereas lower difficulty slow timescale, starvation and tiring, and gives smaller and easier daily tasks but less bonus pay.
Honestly easy is the best for general gameplay if you aren't super hardcore and grindy, normal is fine too but it feels just a bit too fast