Risking declining a postdoc offer for a potentially better one
Accept the "good postdoc" position, get paid whilst you finish your PhD (during evenings/at weekends) and benefit from the position. Apply for the "reaching for the stars" postdoc. Should you be successful, quit the "good postdoc," optionally after negotiating a delayed start date to allow more time in that position.



The OP has declined their other, so this answer is for other readers.