@Humay Vahid @B Robinson @Greenspan, Robby
You are not alone. Many other people want the same thing. e.g.:
https://v4.hkg1.meaqua.org/en-us/answers/questions/5610414/how-to-re-add-agenda-pane-in-new-outlook
You can vote for and leave your comments on these New Outlook Feature Request
My Day panel should be more customizable (My personal favorite) https://feedbackportal.microsoft.com/feedback/idea/85e41bd9-7dbe-f011-aa43-7c1e526e4a18
Please restore right-hand agenda panel on calendar https://feedbackportal.microsoft.com/feedback/idea/2fb47d9a-f650-f011-95f2-7c1e52a55eeb
Right-hand Agenda Panel
https://feedbackportal.microsoft.com/feedback/idea/53305f33-a760-f011-95f2-7c1e52a55eeb
Please return the expand agenda view on the right hand when Calendar is open to month view https://feedbackportal.microsoft.com/feedback/idea/0e520497-7fba-f011-aa44-7c1e5298a4a1