How long has it taken you to complete the main story?

I'm about 4 hours in and really enjoying it so far—every run keeps throwing exciting new stuff at me. Xbox says it's around 13 hours for the "main story," but from reading some spoiler-free reviews, it sounds like the endgame might get dragged down by RNG a bit.

Just curious how long it took others to finish, and if that late-game RNG grind felt as rough as people are saying?