The use of Bookmarks is the recommended / preferred way to save selection states. You would set your selection, create a bookmark and then open the bookmark instead of the sheet:
This can also be achieved with an extension object as mentioned by Bella. However you should check for an object that has been submitted to Branch at: Qlik Branch - you can learn more about extension objects and branch here:
However I am not sure if one exists that supports a default selection.
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