Differentiate between Delete (delete a list) vs Clear tasks (delete crossed off tasks) or Restore Deleted List
In the options tab after opening a list, change “delete” to “Delete this list” then add a final pop up confirmation to confirm PERMANENT deletion of the list!! to make it obvious it’s going to delete your entire list permanently. I just accidentally deleted a long standing and important list of recurring reminders thinking I was deleting all crossed off tasks (your equivalent of clearing all completed tasks) and I can’t get it back.. perhaps keep deleted lists on a separate “deleted lists folder” which will be removed after a week or 30 days etc similar to how you save “completed” tasks, which can then be deleted permanently. If you are not paying close attention to the different variations of the app’s definitions of delete vs clear, it is easy to get confused. This suggestion is bare minimum. there should a way to restore accidental list deletions.