So I've been doing my 2nd play through, I know a few other people have done this but in case you have finished the game, want to play more and haven't tried this i definitely recommend it!
1) Very hard (obviously)
2) Turn off ALL of the HUD including enemy health, concentration & both path finding. I leave the aiming sights on though because its stupid difficult without and even if HUD elements are off they still flash up automatically when required like taking damage
3) Set your active quest to a weapon tutorial, this removes the quest marker from the screen and stops new quests becoming active
4) Don't mark anything
5) Don't mark paths of machines
6) Don't use focus to find out where machines are, i only use it for quest requirements, seeing if that rabbit you need is in the area or spotting those hidden chests
7) Don't fast travel
I tell you its like a whole new game, Ill be walking around hear a machine, slowly edge around it looking for its friends then Aloy will say something like "Ooo this looks like something i should use my focus on!" LOL I look at my map and I've stumbled over a quest i haven't finished yet and I can use my focus and progress the quest without ever activating it
Removing that yellow quest marker and the HUD really makes you look at the world a lot more and then , swapping to the map to see a quest marker your after
Disabling fast travel also gives you more time to enjoy the day / night cycle of the world and really consider "do i want to go over there and do that because its going to take me a while to get there and back?"
I'm also trying to score the good weapons as quickly as possible which means hunting bigger prey than my level which is fun as well and I'm trying to do all the cauldrons first so i tend to try and get the machines to do the killing for me
If your bored try this out, its like a whole new game! 🙂 just wonder around with no active quest and enjoy the world! 🙂