Before the pandemic, when Norwegian was operating the route, Delta planned to fly to Gatwick using a Boeing 757 without Delta Suites. It was totally obvious what they were doing, with a product well-matched to Norwegian’s.
This was supposed to start in May 2020, but didn’t happen because of the pandemic – and because Norwegian ceased its transatlantic flying. Now that JetBlue offers a real business class on the route, Delta has upgraded to a Boeing 767.