You need to adjust the surface area of the water in your incubator. Humidity is determined by how much surface area of water there is in an incubator, not the amount of water. For example, one incubator has a big jug of water in it that holds a quart of water. The opening of the jug is 3 inches square. A second incubator has a damp paper towel on the bottom that only holds one cup of water. The paper towel covers 10 square inches of the incubator. Even though the first incubator has more water in it, the second
incubator will have a higher humidity.
Most incubators have water troughs built in that you can add water to for controlling humidity. If you add water to the troughs and you find it's not getting high enough, which can definitely be a concern during lockdown, you can add baby food jars or mason jars full of water with paper towels or sponges sticking out of them to wick water up and add even more surface area. Or just place a damp sponge or paper towel in the incubator (not touching the eggs).
If you add water to your troughs and the humidity is too high, then you can instead just add a folded up damp paper towel and fold it smaller until the surface area is small enough that the humidity is where you need it to be.