Thanks for looking!
I managed to get it working (sort of) by giving the entry a negative weight (otherwise it is sorted below all my other, unweighted items instead of above), and the specifying .Paginator.Pages.ByDate.Reverse.
The paginator still shows the weighted entries in the bottom of page 1 however, disregarding the date of the unweighted entry…
I guess that’s something I can live with