The voltage-divider-tied-to-3.3V trick allows shifting the level of an input voltage to another range. But there are a few issues with it.
The first one is that we still cannot measure anything above 3.3V this way. Regardless of the values of Z1 and Z2, higher voltage would cause Vout to rise above 3.3V: not good for the ADC.
We could consider combining two voltage dividers, i.e. the first to reduce the voltage swing, feeding the second one for level shifting, but generally that’s not a good idea:
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