Yes. On the official Marriott website, the room selection page for the Durham Marriott Hotel Royal County now has this: "Please note - From September 2022 this hotel will be transitioning to a Delta Hotel by Marriott. We expect minimal impact during your stay."
I stayed at the Durham Marriott Hotel Royal County a few months ago. Although the building is old (apparently with numerous additions over years) and has an odd maze of hallways and rooms that could use a refresh, I was happy with our stay. As a Titanium Elite member, weeks before our arrival, I was upgraded from basic "Deluxe Room" to a "Superior Riverview Room, Larger Guest room, 1 King." The breakfast buffet in a spacious restaurant was a pleasure. Our room, while dated, was large, clean, and comfortable.
In the US, Delta Hotels often have "The Delta Pantry" as an alternative to a traditional Executive Lounge, instead of providing breakfast in the restaurant as an alternative. (This is allowed for Delta Hotels in the Marriott Bonvoy Terms & Conditions.) I hope the Durham Marriott Hotel Royal County will keep its excellent breakfast buffet as a benefit for Platinum Elite and above, despite rebranding to Delta Hotels.
Another "feature" of Delta Hotels in the US is that they often have uninspired locations along highways because they were built under brands such as Ramada or Holiday Inn over the past 50 years. In contrast, the Durham Marriott Hotel Royal County has an excellent location a short walk from the historic center of Durham.
If the Durham Marriott Hotel Royal County had to be rebranded because it's too quirky compared to "normal" Marriott Hotels, it's too bad that the decision wasn't to bring it up to the standards of Autograph Collection or Tribute Portfolio, were individuality and quirkiness are positive attributes.