Hi man,
You have to “Spawn collectible” only 1 time,
when it isccollected by the player you have to say to a variable that this collectable must not be spawned again.
For Example you have to:
set an array of booleans, or better stuff…
You start the game with all booleans set to 0,
when the player collect an item, you have to set the corrisponding boolean to 1, so you can keep track of wich item spawn.
When saving the game, save this too in to a savegame
So when the game start, you load the file and check
If some of the boolean are 1, then dont spawn that item, or delete that item from the level.