[Suggestion] An idea to replace pneumonia for cave debuff
Instead of debuffing the character with pneumonia in a cave, the moist environment adds wear and tear to your constructed items. Building pieces, deployables, and crafted items (even in your inventory and hotbar) take small damage over time as they degrade from the cave's humid and dank interior. A dehumidifier can still counteract this damage.
IRL, high indoor moisture and humidity can cause mold, disintegrating / decaying woodwork, fried electronics, and increased insect activity that can be damaging.