I don't think you are on a fool's errand. You will not be happy until you find out what is possible at your location, and you will learn a lot.
I encourage antenna experimentation, and learn something every time, especially when it doesn't work. Then I have to figure out why.
The tvfool report is only a computer simulation, and is often way off with 2Edge signals, especially with rough terrain.
Your Noise Margin graph seems to indicate that I will never pick up the Seattle UHF channels from my site in Sequim.
It indicates that it is impossible to receive signals that are below the Thermal Noise Floor at -106 dBm. If a signal is stronger than that at your location for whatever reason, you do have a chance of receiving it.
Signal Strength, Signal-to-Noise and Other Related Topics
An antenna with a lot of gain can't "pull it out of the noise" below -106 dBm. And a preamp certainly can't do it because it adds its own noise which degrades the SNR. First, the antenna must increase the signal strength, which it does without decreasing the SNR, to allow for the minimum required SNR of 15 dB and the noise figure of the preamp. Then the preamp can make the signal strong enough to overcome the tuner noise figure and the distribution losses.
This means that the signal must be at least -91 dBm to allow for the minimum required SNR of 15 dB. This is what the tvfool report calls 0 dB NM. You can see that the difference between the NM and the signal power is a constant of 91 dB.
The report assumes that you are using a preamp, which will bury the tuner noise figure in the amplified noise floor. But, if you are not using a preamp, you have to allow for the tuner noise figure, which is about 6 dB. That means the minimum signal without a preamp must be at least -85 dBm (NM +6 dB) where most tuners drop out.