Can I change the sender name (display name) for email campaigns?

Unfortunately no. Microsoft Office365 ignores any change to the "From" (i.e. Sender Name or Display Name) when sending mail and instead defaults to the Display Name set for you user account by your IT administrator. We can't affect how the sender name appears and instead the IT administrator has to update your settings for you.

You can send this help article to your administrator and ask them to change your user display name: https://docs.microsoft.com/en-us/microsoft-365/admin/add-users/change-a-user-name-and-email-address?view=o365-worldwide