Source Eidos Montreal https://tombraider.square-enix-games.com/en-us/news/shadow-of-the-tomb-raider-difficulty-and-accessibility
We’re not stopping there because we’ve made it possible for players to independently adjust difficulty for puzzles, traversal, and combat. There are four unique settings for the aforementioned trio: Easy, Normal, Hard, and Deadly Obsession. While traditional options like easy, normal, and hard can be swapped at any time, once a player chooses Deadly Obsession, it applies to all three categories (puzzles, traversal and combat) and they will be unable to change the difficulty for the remainder of the playthrough. Choose-wisely…
A loyal friend to any Tomb Raider completionist, Survival Instincts is back once again. Adventurers looking for a more holistic experience can toggle Beacon (next objective location) and Glow (interactable objects) on/off regardless of difficulty settings (except when on the Deadly Obsession setting, of course).
For a deeper look at the game’s difficulty settings, feast your eyes on the breakdown below.
Set exploration to easy, for example, and you'll see obvious white paint on the critical path, enjoy a longer saving grab timer and base camps are lit. Put exploration on hard, however, and there's no white paint on the critical path, you have a reduced saving grab timer, there's no Survival Instincts during exploration and base camps are unlit.
Here's how it looks:
Set puzzles to easy and Lara will give you direct hints on the next action to perform. Survival Instincts will highlight interactable objects, and highlight objects necessary to progress in blue. You also get a longer window of opportunity for timed mechanics.
Put puzzles on hard and Lara won't give you any hints, there's no Survival Instincts and you have a shorter window of opportunity for timer mechanics.
Here's how it looks:
Talking of Survival Instincts, you can toggle beacon (next objective location) and glow (interactable objects) on or off regardless of difficulty settings, except when playing on Deadly Obsession.