[maxheadroom]

>So, I assume that recording in public spaces is illegal in general and they make a specific exception to allow dash cams on the conditions mentioned?

The act of recording isn't the problem but the retention of the data records. If you have no need to keep a recording of a day's video for any purposes, then that falls under the provisions of likely being exploited data (e.g.: being used to build a profile of a person's travels throughout the day, week, year, etc.).

In the sense of the allowances, it's about balancing the need of the data's use (e.g.: in car accidents) versus the privacy impacts to other individuals (e.g.: you post your dashcam footage to YouTube and don't obfuscate faces or license plates).

An example of this, pre-GDPR, was when Google was forced to obfuscate faces and license plates in Google Maps for Street View.