Microsoft 365 features that help users manage their subscriptions, account settings, and billing information.
Hi T Mo,
Based on my test, it's not feasible to set a restriction which prevent users setting Due Date to the same day. We understand users may have the requirement to set a specific range for the Due Date when member assign tasks. It is suggested you submit the feedback via Planner Uservoice. This is the best way let the related team hear your voice. Your feedback will help us perfect our products and services.
Thanks for your understanding.
Tim