Crafting in 99 Nights in the Forest is best understood as five gates in a row. The first three are resource gates: farm more wood and metal and you pass. The last two are content gates: they need items that only come from temples, strongholds or long raids.
That distinction is why so many runs stall at the same place. Players arrive at Bench 3 with thousands of wood, discover Bench 4 needs gems, and realise their entire economy was pointed at the wrong resource.
Plan for Bench 4 while you are still on Bench 2
Cultist Gem sources include the Ice Temple, fishing, Cultist kills and the Cultist Stronghold. Two of those — the Ice Temple and the Stronghold — can be run in the same loop, so the cost of preparing early is much lower than it looks.