Thunderbird - Filter for To-Do's in "Today; next 7 days, etc." also for Start-date

[update-freak]

I use Baikal with Thunderbird (Win11) and aCalender+ (Android; with Davx5).

I create my tasks with aCalender+. There it's only possible to set a due date.
When I filter these tasks to show e.g. all of the tasks from next week it displays all tasks because all tasks has no start date (which generally makes sense). But in my case this means I have to add all the Start-days for all of my tasks. Therefore it would be great if there could be added a possibility to use the Start-date instead of the Due-date for filtering for "today, next 7 days, etc.
Another possibility would be to automatically fill out the start date with the due date when there is no start date.

[Jon]

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