After 4 days the cut gets dry and hard at about 6 days it might start to mold. You can cut the mold but rather cut too much than too little.
If you regularly cut the bread it can be used longer without molding. The crust doesn’t mold that fast.
You absolutely can’t cut the mold with bread. If it shows moldy spots, the fungus already penetrated the whole piece, even if it’s not visible. You can remove mold from hard food like cheese or foods that are high in sugar like marmalade.
You are probably correct, but if you cut a huge piece of you at worst probably only will get diarrhea