Earlier quoted context omitted.
Just an idea - you could try putting them to bed 15 min earlier every few days, and if they have trouble sleeping put on a short kids audiobook. Two of the most peaceful I know of from Audible are “The Tailor of Gloucester” read by Meryl Streep and “The Little House”.
Also depends on how young they are, if they are of reading age, then putting them to bed a little earlier and then allowing them to read for 15-20 minutes on their own can also be another way of calming them down. Some of the kids mindfulness podcasts (Peace Out as an example) are also good for this kind of thing
The one of reading age is already reading after he's in bed. The hard part is getting him to stop and actually go to sleep.
I will look into the podcasts; thank you for the suggestion!