[1.18] Update BlockEntity nbt

I'm trying to make a block with gui, where save and load some NBT data.

I put my data in method. But if quit and join to world, data is empty. How to update nbt?

@Override
protected void saveAdditional(CompoundTag nbt) {
  nbt.put("mykey", myvalue);
}

Edited November 19, 20222 yr by xkorot