MacBook won't sleep

Hello,

This article has things to check when this issue occurs. I am including the bullet about connected devices because your mention external monitors but think one of the earlier points form the article is a more likely cause.

If your Mac sleeps or wakes unexpectedly - Apple Support

• "Connected storage and devices: Malfunctioning USB and Thunderbolt storage and devices may keep your Mac from going to sleep. Disconnect those devices and see if your Mac goes to sleep. If it does, reconnect each item, one at a time, until you find the one that’s malfunctioning. Contact that device’s manufacturer for more information."

I hope this helps.

My 2020 MacBook 13 Pro is doing the same. when I press the lock button to put to sleep it will lock then stay lit up the whole time. do it when connected to external monitor as well as when just the notebook. I also think it isn't sleeping fully when in clamshell mode, no monitor hooked to it as it has been dead every morning this week when closed with full charge.