Trump is one man against pretty much the entire DC power structure.
I find it hard to blame him for picking and choosing his battles; this is a constant war and I suspect that he has other ideas for how to get the wall funding past the GOP cucks.
The swamp is like Hannibal and Trump is Fabius Maximus. His agenda may not be able to survive a pitched battle, but he can slowly starve them out, even if it means that he has to cede the battlefield from time to time in order to keep the advantages he has.
There is only one way, and one way only, for Trump to get the respect born out of fear he needs to impress both Parties of Congress. The Veto. If he signs a bill including funding Planned Parenthood and denying funding for the Wall, he will have lost all credibility with Congress and his Movement base.