"[They] feel very rewarded from their work," the source says.
The source also says that they have no concrete plans on a return to the U.K. amid the coronavirus pandemic, though there are occasions they are monitoring.
"Decisions will be made on a case by case basis and see where the medical protocols are around the time they decide to return," the source says. "Certainly, the Duke and Duchess have their eye on the Invictus Games, Trooping The Colour and Prince Phillip's birthday in June, and the unveiling of the Princess of Wales statue."
"Things can obviously change, if there's a concern about family health, but they are not hopping over the pond anytime imminently," the source said at the time, adding that the royals are adhering to "social isolation guidelines" amid the coronavirus pandemic.
Meanwhile, on New Year's Eve, the couple posted a heartfelt message for 2021 on their Archewell website. The post included two photos -- one of Harry as a child on his late mom, Princess Diana's, shoulders and another of 39-year-old Meghan as a kid posing with her mother, Doria Ragland.
"I am my mother’s son. And I am our son’s mother. Together we bring you Archewell," the message reads. "We believe in the best of humanity. Because we have seen the best of humanity. We have experienced compassion and kindness, From our mothers and strangers alike."
"In the face of fear, struggle and pain, It can be easy to lose sight of this," the message continues. "Together, we can choose courage, healing, and connection. Together, we can choose to put compassion in action. We invite you to join us. As we work to build a better world, One act of compassion at a time."
For more on how Harry and Meghan spent their first Christmas in the U.S. with their 1-year-old son, Archie, watch the video below.