If you’re playing Genesis Part 2 and you come across a loot drop open it and one thing i’ve found on official is that some drops give lots of pipes, generator wires and water irrigation pipes which is basically free food for the gachas! You can also grind them for resources and craft them into other items/structures of your choosing aswell! Hope this helps.
I highly recommend you see how many walls you need to take this before you give it any, so that way you can take it first try. If you take multiple trips then it’s percentage will decrease. Also if you can’t hold all the walls it takes then out then in a storage chest near where the Gacha is. This saves a lot of stress because you can take your time making the walls without worrying about the percentage lowering.