As the game no longer allows you to load old worlds, it also doesn't allow you to re-create an old world, an action that would likely be desirable (given current circumstances with 21w06a) and wouldn't affect the original world.
MC-215156
Re-creating a world pre-21w06a is impossible
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We're tracking this issue in MC-214779, so this ticket is being resolved and linked as a duplicate.
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