Standby Mode: Turns off after several hours

Similar question/post here, but it wouldn't let me reply.

Basically, I put my phone in Standby mode (iPhone 16 Pro) by placing it in landscape in a wireless charger. It works fine. But after several hours (I go to bed around 9:30....this happens sometime around around 2a), it goes black. Like the other post says, I can tap to turn Standby mode back on, but that essentially negates the value of the feature (it's supposed to be a nightstand clock replacement).

Anyone else having this issue? Can someone from Apple chime in?