Startup Idea: Comprehensive To-Do List and Timeline Management Application

Startup idea to develop a versatile to-do list management software focused on tasks and timeline management for event planners. The application should provide features such as recurring reminders, one-off reminders, reminders linked to different accounts, and functionalities to integrate with the internet to find needed contacts and integrate with Google Calendar for meeting requests.

A big problem I have at work is a good to-do list management that is not anything like some program management board. This should be more like an app that can have recurring reminders, have one-off reminders, and have reminders linked to different accounts. I work in wedding planning and events planning and most of what I do is list management and timeline management but for external lists and need the ability to have the internet integrate to find numbers and emails needed and also send meeting requests to google calendars.