Every court that reviewed Trump's DACA case said exactly the same thing:
Trump has the authority to write a new DACA policy - but - Trump does not have the authority to declare Obama’s DACA policy unconstitutional.
On Trump's first day in office Trump could have written this two sentence Executive Order:
“According to the exact language in the Immigration and Nationality Act of 1952, the DACA kids are unlawfully present in the USA. Consequently, I order the Secretary of Homeland Security to remove them.”
An E.O. worded like that cannot even be reviewed by a federal court.
Unfortunately, time and again, Trump has made it crystal clear that he does not want to deport any illegal immigrants except dangerous criminals.
Trump does have the authority to declare O’Bummer’s policy unconstitutional and the order you described would have been blocked by leftist judges too just like everything else he does.