Hello Abhay,
Welcome to the Microsoft Community. I am a Microsoft user like you, I hope you are doing well.
To disable a single click to open email in New Outlook, you must change the reading pane settings in your Outlook options. Here are the steps you can follow:
• Sign in to your Outlook account using your email address and password.
• At the top of the page, select Settings and choose View all Outlook settings.
• In the Settings pan, go to Layout and select the Reading pane under Maile.
• Under Mark as read, uncheck the option Single click to open items.
• Click Save to apply the changes.
I hope this helps you disable a single click to open the email in New Outlook.
This answer is wrong and should be deleted. There is no such setting as 'Single click to open items".