Does the always on feature stay on when charging or in the dark

The answer is a YES with exceptions. More information here 👉 Use Always-On display with your iPhone 14 Pro or iPhone 14 Pro Max

Axel F.

It’s pretty useless as a nightstand clock since it goes fully dark even if it’s powered with a cable and battery preservation is unnecessary. Sure, you can tap it, but in the middle of the night you may want it just glance at it to see the time.

Is there no mode that really really keeps it on?

Read the Related Article above your post. It has a listing of when the iPhone screen will go dark when using the Always On feature.