Perhaps Trump doesn't live his own life by the values that Evangelical Christians maintain are important. But if Roe is struck down, it pretty much guarantees that a group of people will think he was the best President ever for decades to come.
Here's the problem though - while I have no doubt that a subset of the population will applaud Trump should Roe v Wade be reversed, these people are in the minority. By all accounts 2/3rds of Americans want at least limited availability to abortions. Making abortion illegal under all circumstances is an unpopular opinion even among registered Republicans, and particularly unpopular among people under the age of 50.
So... like with Trade and Tariffs and Foreign Policy Trump is going against decades of his own party's platform in order to satisfy the most vocal minorities within the party, and quite possibly at the expense of future Republicans.

Yeah... but as far as I can tell, the Republicans who think abortion should be legal under some circumstances aren't militant about it... they don't really care that much. Like, the ones I've talked to are like, "Oh, yes, I definitely think there should be an exception for rape and incest, but..." *trail off, shrug* "I mean, it
is still a baby..." *looks uncomfortable, changes the subject to how the democrats all want to tax us to death or something*
Like, they really don't give a shit. Making a girl who's been raped by her father carry a fetus to term makes them sort of uncomfortable, but... they are still pretty okay with just ignoring the implications for the actual, born girl who will have to suffer through this. They minimize it, or they say, "Oh, that's not very many of the cases" or something -- anything -- that will let them change the subject.
They don't give a shit about the actual already-born women. They are actually less comfortable with the idea of being on the same side as a filthy liberal than they are with the idea of forcing a woman to carry a fertilized egg to term no matter what the consequences are to her. Trump and the GOP know this. So they push for an end to Roe, knowing it will whip the whackadoodle far-right fringe into a cheering, whooping frenzy, and hoping this formula that is working for them so far keeps working.
Which it probably will. Because even though under the GOP, the US will go back to the closet coat hanger abortion era, at least transgender Muslim Mexicans won’t overthrow the government and impose sharia law and universal health care.