Returnal will have you going through the same area following every death, with several changes and giving you more things to unlock as you progress further into the game. After you defeat Phrike, the first boss in Returnal, you’ll receive a datacube. It happens immediately after you beat the boss, and the device next to it turns it into a new consumable device you can find in future runs. When you die and repeat through the game, datacubes can appear again, and you’ll need to turn these items, unlocking more consumables.
When you want to exchange a datacube for consumables, you’ll need to defeat the boss in the region you found it. Where you turn it in will vary each time you find a datacube. If you find a datacube in the Overgrown Ruins, then you need to defeat Phrike, and submit it to that item. When you find one in the Crimson Wastes, you need to defeat that area’s boss and submit it for a new item. You’ll need to do this every time you find a datacube on your run, and you need to place it into the device that converts the datacubes. The device does not appear to move around or appear in locations outside of the area after defeating the region’s boss.
There are 18 consumables to unlock, so the more often you want to find these devices, you have to explore more and seek them out.