If I press 0 that would indeed be the right value for that case. However, I would like it to continously send the last value I pressed circumventing the automatic drop back to 0.
I don't think what you want to do can be done, then. You can't "press a 0". If you are not touching the sensor, the value that it returns should be 0. When you do touch it, the value read ramps up to some value and then back down to zero when you release it. The Arduino reads a number of values along that curve.
If you want to track the highest value in some time frame, and use that value for some time, that could be done.
But, the Arduino can not tell whether a reading was of some particular meaning to you, and should be maintained until it no longer means anything to you. It does not have an ESP sensor built in.