Whether or not he WANTS to remove protections for pre-existing conditions he is litigating in a way that will do exactly that.
As far as the law being written that way, clearly not. This is exactly the absolutely bonkers interpretation of the Constitution that Texas is trying to use. SCOTUS will almost certainly not rule in their favor if for no other reason it would send the US legal system spiraling into insanity.
As for having one without the other, you most certainly can as evidenced by the last two years. In case you weren't aware of how utterly insane the right wing argument is here, let me break it down, and this is not exaggerated. It is legitimately this lawless.
1) If the government says you must get insurance or else it will punish you with fines, this is constitutional because the fines are a tax.
2) If the government says you must get insurance or else it will do nothing, this is unconstitutional because the nothing the government will do to you represents an unconstitutional burden.
3) If the mandate to get insurance on penalty of nothing no longer exists the entire ACA must be invalidated because clearly Congress did not intend the law to exist without the nonexistent penalty. They apparently did not intend this despite explicitly passing a law that did exactly that.
Yeah, that's the side Trump's on. Lol.