You typically make the change in the template, then save those changed to your style library. What you seem to have done is simply change them in the template but not push those changes to your style library. After making the changes and exiting from the style manager.. hit the "save" button on (manage tab..Styles and standards section right above update and purge) then when you create a new drawing using that template it will have the correct line weights.
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Inventor 2023 - Dell Precision 5570
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