Hi Salman,
Yes I believe you will need to licence the extra 8 cores, and also I will suggest you review the FAQ section this site and https://wintelguy.com/2022/ms-windows-server-licensing-faq.html
And also the calculator https://wintelguy.com/windows-per-vm-licensing-calc.pl
Please check your CSP or licence provider as they might be able to help you in providing you some detail information on the licence costs and if you are covered under the licence agreements.
Hope this helps.
JS
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