Thanks! I checked, and at least in the EU, every country has a law that gives workes the right to take a break after 6 hours, as this comes from the "Working time directive", see e.g. https://www.eu-info.de/europa-punkt/politikbereiche/arbeitszeit/ The UK still has a corresponding law, too, see https://www.gov.uk/rest-breaks-work
If I had to implement this, I would set up a data structure that with "maximum daily work time before first compulsory break" and "minimum break time after that maximum work time", and then a variable for the number of such compulsory breaks (2 for Germany). Keeping track of 27 national labour laws is probably not what writing this software is about, so I would be happy to fill the data structures for whatever legislation I am in.
Extra bonus for checking that the minimum break has been kept between the end of the previous working day and the start of the next one (11 hours for Germany, again from the working time directive).
Will find a workaround by doing the calculation with exported data in Excel, but I would certainly be prepared to pay for a software that saves me having to do the calculation by hand!