In addition to Destiny 3, it was also reported that "something like a classic version of Destiny 2" has been greenlit.
Destiny 3 is in development. And they also greenlit something like classic D2, which is why the roadmap has shifted significantly.
Soon, informant Colony Deaks confirmed:
Yes, Destiny 3 is in a very early stage of development […]. We have been holding this information for several weeks and wanted to wait to disclose it until the project takes shape […]. We plan to share additional information in the coming months.
Rumors about Destiny 3 first appeared in 2018, but development was not underway then. Destiny 2, after the launch of the "The Final Shape" expansion, showed a minimal audience on Steam, and Sony recorded a $204 million loss due to low sales. This may have pushed Bungie and Sony to create a new installment in the franchise.