Thanks for posting here in the Google Nest Community.
A few things: is your alarm in the morning at Sunrise alarm? What is the brightness setting on your Nest Hub 2nd gen? What steps have you taken so far? Is the Ambient EQ feature enabled on your Nest display? You can enable this feature and observe if this will give you better results when the alarm goes off. Check the steps below.
Check this link for more information.
Hope this helps.
Happy to hear that those steps worked for you, and @Juni was able to help. It looks like we can consider this one complete, so I will lock the thread shortly unless I can help out with anything else.