In Early September of 2017, DACA was rescinded by then-Acting Secretary of Homeland Security Elaine Duke via a Department Memorandum. The Supreme Court struck down this memorandum in mid-June of 2020 because it was found to be arbitrary and capricious under the Administrative Procedure Act, which requires a valid reason for all administrative orders. In late July of 2020, a new memorandum was issued by de facto Acting Secretary of Homeland Security Chad Wolf, again rescinding DACA. However, since then two federal courts have found that Wolf is serving illegally as Acting Secretary, and overturned several of his orders, including this DACA rescission, again reinstating DACA. Why didn't (and doesn't) Trump just use an executive order rescinding DACA, sidestepping both the need for a valid reason and the possibility of the person issuing the order serving illegally?
Original Rescission: https://www.dhs.gov/news/2017/09/05/memorandum-rescission-daca
Court opinion overturning first rescission: https://www.supremecourt.gov/opinions/19pdf/18-587_5ifl.pdf
Court opinion overturning second rescission: https://www.nilc.org/wp-content/uploads/2020/09/Batalla-fourth-amended-complaint-2020-08-28.pdf