You shouldn't need to duplicate them if you're not changing the promotion code. Simply edit and change the dates in "Start date of validity of this promotion" and "End date of validity of this promotion". Best I can suggest is try using the Conditions to replace those parameters behavior so you can use a substitution for the year. The below might work for example.

First condition: This condition:
Date A, Field A or Value A: Order Date of the order wanting to use this promotion
Date B, Field B or Value B: Constant Value or String (CB substitutions can be used)
Value B: [cb:date format="Y" /]-12-01
Condition 1 (> for Dates): For dates: Date A > Date B (Date A must be later than Date B )

The above should result in the date they're purchasing having to be greater than YYYY-12-01 (e.g. 2020-12-01). The [cb:date format="Y" /] substitution should always output the current year.

Now you'll need a second condition to cover the end date. The below should cover this as well.

Second condition And/Or: AND
Date A, Field A or Value A: Constant Value or String (CB substitutions can be used)
Value A: [cb:date format="Y" /]-12-31
Date B, Field B or Value B: Order Date of the order wanting to use this promotion
Condition 1 (> for Dates): For dates: Date A > Date B (Date A must be later than Date B )

The above should result in the date you're purchasing having to be less than YYYY-12-31 (e.g. 2020-12-31).

You might be able to use a single condition for this, but I've not tested such a usage. That would be done with the following instead of the 2 usages above.

First condition: This condition:
Date A, Field A or Value A: Order Date of the order wanting to use this promotion
Date B, Field B or Value B: Constant Value or String (CB substitutions can be used)
Value B: [cb:date format="Y" /]-12-01
Condition 1 (> for Dates): For dates: Date A > Date B (Date A must be later than Date B )
AND Condition 2 (< for Dates): For dates: Date A < Date B + 1 month (Date A must be earlier than 1 month after Date B )

The above adds 1 month to Value B then makes sure the order date is less than that date. It's less specific than the 2 conditions, but it's easier to configure and frees up a condition slot encase you need other conditions.