Does it really matter if he is saying something because he believes it or if he just thinks voters will like it?
There is something to be said for a political figure who has some basic coherent system of seeing reality, just because it seems more likely such a person will make reasonable decisions. With someone like Trump you always wonder of he ill just change direction with the wind.
But in the more immediate pragmatic sense, part of the job of political leaders is to see what people want and care about, and to offer policies related to those things. Sometimes even if they personally aren't so attached to the issue. Or to put it another way, a political leader who says, fuck what the people think, I am just going to do what I think is right, doesn't know his job. Yes, it would be nice to see someone do that because they believe in democracy, but wanting to be elected also works.
Nor is stealing a rival's policy ideas a new thing, every political leader does this.
That being said, DeSantis really does have an advantage, or many advantages, in part because he seems more authentic.
I have come to think that the kind of people who just think if Trump says it, it must be bad, are kind of hopeless. When you dig down, may of Trumps political policies were barely different from Obama's, including ones progressives freaked out about. And Biden has also continued with a good number of them. If people won't actually look at things apart from partisan associations, I don't really think there is any hope for them to think about the issues. Which is depressing in terms of what will happen in the US I guess.