Slapping a barcode on a sensor is a lot less involved than using it to take some careful measurements and then storing and retaining the results.

Or to just dither the hell out of your image.

Luminance sensitivity information could probably be most-easily detected in the dark areas of an image. So just crush those areas.

I suspect the more you think about this problem the more the answer becomes: Compress your image in order to remove information density.

Still, a determined adversary might find this information discernable over a long enough series of images.

Most phones do that for you anyhow. Unless there are serious defects in the sensor that would probably mean it would fail QA even for bargain bin phones the amount of “AI” post processing that phones do these days is probably sufficient to erase any sensor fingerprint.

Even with DSLRs and RAW files you often don’t get a RAW output from the sensor all of them do their own “color science” magic and other alterations like denoising too even on the rawest of the RAW settings.

RAW files today just mean that the files are uncompressed or the least compressed since there might be some compression/downsampling happening at readout anyhow and that you get a ton of metadata that can be used by a photo editing app to better work with the image.