Of course it is. DACA was implemented by executive action, and it can be removed by the executive. No one, not even its supporters thinks otherwise.
If you did basic research on the 2020 Supreme Court decision Department of Homeland Security v. Regents of Univ. of Cal., you'd see that the Roberts court said that the Trump administration could rescind DACA – they just had to follow the basic "procedural requirement that it provide a reasoned explanation for its action":
"We do not decide whether DACA or its rescission are sound policies," Roberts wrote. "The wisdom of those decisions is none of our concern. Here we address only whether the Administration complied with the procedural requirements in the law that insist on 'a reasoned explanation for its action.' " ...
But, as Roberts observed, the attorney general offered no detailed justifications for canceling DACA. ...
As Roberts noted, Duke's memo didn't address the fact that thousands of young people had come to rely on the program, emerging from the shadows to enroll in degree programs, embark on careers, start businesses, buy homes and even marry and have 200,000 children of their own who are U.S. citizens, not to mention that DACA recipients pay $60 billion in taxes each year.
None of these concerns are "dispositive," Roberts said, but they have to be addressed. The fact that they weren't addressed made the decision to rescind DACA "arbitrary and capricious," he wrote. ...
Roberts made clear that an administration can rescind a program like DACA, and indeed immigration experts don't disagree with that bottom line. The problem for the administration was that it never wanted to take responsibility for abolishing DACA and instead sought to blame the Obama administration for what it called an "illegal and unconstitutional" program.
Supreme Court Rules for DREAMers, Against Trump - NPR
From SCOTUS blog explains the (very low) bar the court requires here:
Roberts then turned to the central question in the case: whether the Trump administration followed proper procedures in terminating DACA. Under the APA, Roberts stressed, courts should not substitute their own judgment for that of the agency. Instead, he explained, their job is to determine whether an agency made its decision “based on a consideration of the relevant factors and whether there has been a clear error of judgment.” In the majority’s view, the Trump administration had failed to meet even this relatively low bar.
The administration simply needs to show that the considered the outcomes of their decision and believe them to be justified. That's it. I think I understand why you're having such a hard time understanding the requirements: it seems impossible that the Administration could have failed to do this, but they did. So, what exactly is the issue:
The first step in the court’s inquiry, Roberts explained, “is knowing where to look for the agency’s explanation.” The majority focused on the memorandum that acting DHS Secretary Elaine Duke provided when she announced the decision to end DACA in September 2017.
The Duke memorandum,[Justice Roberts] observed, concluded that DACA was illegal and should be terminated because it made DACA recipients eligible for benefits such as Social Security, Medicare and the ability to work legally in the United States. ...
[T]he problem was that the memorandum did not consider the policy that Roberts characterized as being “at the heart of DACA”: the protection from deportation that the program provides. Even if the benefits provided by DACA were illegal, Roberts observed, Duke could have still retained the protection from deportation, but instead she simply concluded, without any explanation, that it had to be terminated as well.
The only justification provided by DHS for rescinding DACA was the issue with benefits and the ability to work legally in the US. They did not even (publicly) consider, explain, or justify the core of the change: the removal of protections against deportation. If they were worried about Social Security spending, they could have simply banned DACA recipients from it. Why deport them, causing real harm? DHS didn't say, and, according to the Administrative Procedure Act, they had to. This isn't a high bar: Justice Roberts made it clear that he doesn't think it's the Court's place to question the agency's judgement – just to make sure they used any at all:
Under the APA, Roberts stressed, courts should not substitute their own judgment for that of the agency. Instead, he explained, their job is to determine whether an agency made its decision “based on a consideration of the relevant factors and whether there has been a clear error of judgment.”
This isn't a particularly contentious view. In his dissent, Justice Kavanaugh agrees with the majority that the 2017 Duke memo does not satisfy the APA's "arbitratry-and-capricious standard". His disagreement is on whether a later 2018 memo released by Homeland Security Secretary Kirstjen Nielsen, which provides additional justifications, should be accepted. Roberts and the majority argued that this memo was a post hoc rationalization, and the policy change needed to be justified based on the explanation given at the time the change was made, while Justice Kavanaugh would allow later explanations:
Nielsen's issued her memo after a D.C. district court vacated the Duke rescission and gave DHS a chance to reissue a memo rescinding DACA that provided a fuller explanation. ... Nielsen's memo gives reasons that don't appear in the Duke memo, so Roberts said they amounted to "impermissible post hoc rationalizations" and therefore weren't a factor in the Court's decision.
"The Court's refusal to look at the Nielsen Memorandum seems particularly mistaken, moreover, because the Nielsen Memorandum shows that the Department, back in 2018, considered the policy issues that the Court today says the Department did not consider," Kavanaugh wrote.
So, what would they have to do to repeal DACA? It's simple, just go back and rescind the program again, this time providing a reasoned explanation and justification for their action. From SCOTUS blog (emphasis mine):
In closing, Roberts reiterated that the court was not deciding “whether DACA or its rescission are sound policies.” Instead, he stressed, the court addressed “only whether the agency complied with the procedural requirement that it provide a reasoned explanation for its action” – which, in the majority’s view, it did not. The solution, Roberts continued, was for the court to send the issue back to the Department of Homeland Security for it to reconsider and, if it wants to rescind the program again, for it to offer a better explanation
So, they can't just say "the policy is illegal", we need to get rid of it. They need to look at the outcomes of this policy change and provide a reasonably explanation for why these changes are reasonable and justified. If they did that, Roberts made it clear that he wouldn't question that judgement, though the Trump Administration could still be held accountable politically. The fact that they did not, in fact, rescind the program, even after being invited to by the Court, suggests why they did not explain the decision in the first place: they were unable to justify the rescission in a politically palatable manner.