I am by no means an expert but from what I understand
a, you are on Day 21 - by no means beyond hope. It could be a while yet depending on your bator temp.
b. there is a fair amount of rest involved in the process for the chicks. Mine were still and silent most of the time on my last hatch with bursts of activity in between.
c. Intervention only tends to work in certain circumstances. If you go wading in to eggs that haven't even pipped you are only likely to get dead chicks
Personally, I wouldn't rush into any action you might regret. I would still counsel patience but they are your eggs.