A president seriously dedicated to a policy will find a way....

You know, there's a name for that belief. The Green Lantern Theory of the Presidency. The idea that there are no actual constraints, legal or political, on the President. That the only thing that matters to whether they do something they want is their will.

vox.com - The green lantern theory of the presidency explained

But that's not how our government works. Most of the power on domestic issues lies with Congress, not the President. They hold the statutory pen, and they control the purse. For things like immigration, which have been the subject of decades of political debate, the laws that govern the issue are pretty elaborate. Congress has already spoken on most of the hard questions, which makes it nearly impossible for the President to significantly change policy. Where there is leeway in the statutes, resource constraints prevent the President from making major changes. You need money to build walls or hire more border patrol agents or immigration judges or build and staff detention centers....which means you need Congress to give you that money.

So, no. A president seriously dedicated to a policy isn't likely to find a way. They'll just run into the law and the realities of budgeting.