Are you serious? Every politician is an ideologue. It's why we elect one over another. We agree with one's idea about policies over another's.
The only people who we expect to divorce themselves from ideologies are judges, who are there to interpret the law, not make it.
I think most of them are true Republicans in the sense that they want to elect people they think are trustworthy and then let them make decisions as their proxy. In that case, a candidate can have policies and platforms to convince people to let her be their proxy, but she doesn't need them. She could just have a "trust me, I'll make the right decision" pitch.
Besides, if Trump is an ideologue, what is that ideology? At best it's a new (or at least renewed) nativist spin on identity politics. That's not an ideology; that's a team.
Republicanism is an ideology. Trump's is clearly farther right than previously elected R presidents.
He does have a laundry list of issues he tweets about, a subset of which he picks at with executive orders (which, itself, is unconservative) but that seems more like raw appeasement of his political base than anything coherent (or even consistent!).
There are a few exceptions, I guess. He's, at least in rhetoric, for a strong military. Though we're nowhere near a "Trump doctrine" that proposes a coherent framework for that desire. It's, again, more of an id-driven move than anything rational.