You can fast travel back to those locations after completing the story and unlock the treasure chests. You may have noticed locked treasure chests early in the game that required lockpicks. They can be bought from her for a total of 6,100 gold. She is a vendor that sells the two gadgets. After talking to the first four, the fifth one will get marked on the map. The side mission requires you to talk to five outcasts. Lara will agree to look out for the dead man and get back the dice from him. Talk to him (Takiy), and he will tell you a dead man stole his dice. There is a boy sitting at the foot of the hill, close to the market square. The side mission starts in The Hidden City (Paititi) at the following location. To purchase both of them, play the 'Find Takiy's Dice' side mission in The Hidden City. However, if you want to access every area and complete all puzzles, you will need them. These items are optional gear that you do not need to complete the main story.

The lockpick allows you to open locked Conquistador treasure chests. The Rope Ascender allows you to destroy heavy barriers.

The Lockpick and Rope Ascender are unlockable gadgets.

Shadow of the tomb raider rope ascender