I have talked before about them owing you time for stalling. The next idea is to adjust bedtime based on behavior. I haven’t done this yet, but I read about this advice, and I’ll use it when our bedtime routine becomes a bit more strict. Each time a behavior issues arises, you take away five minutes from their bedtime. So, if they have three infractions, they would go to bed at 7:45 rather than 8:00. The opposite of this can also be true. Rather than going to bed at 8:00, with great behavior they can have extra time for more stories or just staying up later than usual.
I do this! It works well!