Hi Shubhamangala Sunil,
I would recommend going to Maldives as the Maldives experience is usually confined to the all inclusive resorts on the beautiful island. So, the Covid situation won't affect your Maldives experience. However, to truly experience Greece you need to indulge in its culture, food and day to day life. Since many places in Greece are still partially if not completely closed, a trip to Greece in 2021 will be sub par to what you will normally get. I am attaching this well compiled page on all things Maldives :
Hope this helps!