Requirements for privacy in terms of biosensors, video and smartphone signals

I'm conducting research employing biosensors (i.e., heart rate and skin conductange signals), video data, smartphone signals (i.e., sensors such as accelereomter and gyroscope and touch data) and handwriting. A big problem is privacy, i.e. users are affected by privacy issues related to the collected data. Now, I would like to relate all these data sources to privacy, i.e. which one is less privacy-invasive and which one is more privacy-invasive. As far as I know, there exists no work relating biosensors, video data, smartphone signals and handwriting in terms of privacy. I only found the following paper: Fanourakis, Marios. "A report on personally identifiable sensor data from smartphone devices." arXiv preprint arXiv:2003.06159 (2020). These paper relates only smartphone data in terms of privacy. A possibility would be to establish a certain number of requirements for privacy and then evaluating the data sources in terms of these requirements. For example, 3 requirements and each requirement could be rated on low (1), medium (2), high (3) in terms of the data sources. So, for example, video data could be rated as low for requirement 1, medium for requirement 2 and high for requirement 3 which would give a total sum of 6 (the higher sum the more privacy invasive). Of course I could just come up with such requirements but that is not very scientific. Do such requirements exist regarding privacy? I was thinking about papers or also law. I know that there are different laws (e.g., the GDPR) but as far as I can see these laws are all pretty fuzzy. I think privacy is also linked to personal identifiable information, perhaps that could also be a way to go by coming up with requirements for personal identifiable information. Of course if somebody knows a work which compares biosensors and smartphone data in terms of privacy, I would be happy to know about it.
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