Crafting a simple task and planning solution in 365 -Planner / Lists /...

Hi Niall_O - sharing a perspective on this one... adding To Do as an FYI. 

Microsoft Lists is an information tracking app that enables teams and organizations to manage a process or workflow (link takes you to our Lists adoption page - that includes our online workshop, too: https://aka.ms/MSLists/workshop). While To Do and Planner are purpose-built apps, specifically designed to help individuals and teams manage their work using tasks. Commonly, when a task is completed, it becomes hidden from view. Microsoft Lists, on the other hand, enables users to collect, view, filter, sort, collaborate, and share structured information across status, life cycle, ownership, and more. Lists integrate with the Power Platform to design, build, and extend productivity apps alongside Power Apps (custom forms) and Power Automate (custom flows).

I also started a related thread on LinkedIn specific to "forms" from various M365 apps/services - might be of interest to you, too: https://www.linkedin.com/posts/mark-kashman_faq-activity-7221203063036923904-CnpE