We are a family of 5 with kids 5,2 and 7 months with US papers.
The stopover is a bit under 4 hours.
Will we have to go through passport control, pick up our luggages and recheck them within that time?
im also accounting the time waiting for the stroller to come up.
flight is with KLM
Anyone had experience with that and can help out? TIA

Are both your flights on KLM? If so, your bags will be checked all the way from LYS to JFK - you won't see them at AMS. You'll also have boarding passes already in hand after you drop off your bags at LYS.

At AMS you will need to go through passport checks before you get to the departure gate in AMS but that will only take a few minutes.
You have more than enough time.

I transit thru AMS pretty regularly. You’ll have to go thru passport control as you’re leaving the Schengen area. You can’t use the egates, so you’ll have to stand in line for immigration.

Sometimes those lines are long, wait 30mins to 1 hour, other times it’s just a matter of minutes.
Either way, with such a long connection time, you have nothing to worry about.

If you’re thru booked & ticketed on AF/KLM, you’ll not see your luggage until you arrive @ JFK.