try this:
WHERE due-date
WHERE date(due-date) <= this.file.day
1 - with date(due-date) you convert the link (due date is a link) in a date;
2 - as your files are daily notes with titles in the format “YYYY-MM-DD” you can use the implicit field file.day, that extract the date from the file name (attention, to not create any conflict, don’t use any field with the name Date::).
https://blacksmithgu.github.io/obsidian-dataview/data-annotation/#implicit-fields
3 - you can do the other “calculations” with file.day: WHERE date(due-date) = this.file.day + dur(1day)
4 - you can use multiple WHERE conditions. They work as multiple “AND”.