MacBook Pro (M2 Pro, 2023) not going to sleep

First thing to do would to Close ALL the applications appearing in your Image above

Second would to update " My 2023 MacBook Pro 16-inch (Apple M2 Pro) running macOS 14.0 (23A344) "

Which is the Initial release of Sonoma back on Sept 26, 2023 macOS 14.0  ( 23A344 )

There have been approximately 15 or 16 updates since that time

Apple security releases

Keep your Mac up to date

To add

This computer also qualifies for the Next Newer Version of macOS 15 Sequoia

macOS Sequoia compatible Computers 

Whatever way you go with this

Always make a Time Machine Backup  before doing any upDates / upGrades 

Better still >>

To truly protect your non replaceable Data

Have a 3-2-1 Rescue Plan in place and always current

3 Backups using 2 methods and 1 off site incase of natural disaster or un-natural disaster.

Each of the above should be done to a Dedicated Single Purposed External Drive 

Below link is intended to augment what TM Backup does 

https://bombich.com

Open Terminal

pmset -g log | pbcopy

Then reply to this post and click the Additional Text button and paste in the power management logs. It typically indicates what is waking the Mac, etc.