OnePlus6 NFC
This question is similar to the one about fingerprint on Pocophone F1.
The difference is there are no schematics available for OnePlus6 and therefore the presence of the NFC can only be listed in the device trees. It's also aliased in the kernel.
The module is probably NXP544 connected over I2C. So in theory it should be possible to enable the peripheral (and regulators) and access it as there is already a driver in the kernel
Again. There is no reserved memory for the I2C or the GPIO pins in the device trees. However, the TZ can be guarding these regions from access from less privileged level.
If it would be possible then also the fingerprint sensor on OnePlus 6 might be accessible, correct?