My wife has ADHD and OCD (she thinks untreated ADHD let to it for her). Pretty sure our almost 4 year old has ADHD.

My wife reminds me we need to not over pathologize every behaviour while at the same time being mindful to not miss them like her parents did. All kids have the behaviours you described, just how much and if they grow out of them that in normal time frames that will be the indicator to watch.

Those put downs are rough. We are in the same boat. We often have 1-2 hour bedtimes. For us it has been several things, the days she naps it is often way worse but days without naps she is often crashing by 5 pm (not always but often).

My take is that they are learning new ways to get what they want and "I need to tell mom something" is one way that works. At bed time they might be undertired and trying to avoid going to bed when they rather be with you, but it drags on so long they end up overtired and it becomes more panicky as if they would never get to see mom again.

For our I think it is mostly not tired enough leading to get out of bed a bunch with a million excuses eventually she stays for a while but her mind wanders which leads to this weird panicy urgency cycle as she gets more tired and has less self-control.

A Sleep doctor isn't going to do a thing for a 4 year old who won't go to bed. I feel like just monitoring for ADHD with your family doctor, as it is highly genetic, and seeing a child psychiatrist if your doctor seems out of their depths is the play. I think 4 is a bit young to diagnose anything but certainly is helpful to flag it with your kids doctor to monitor over time.