This might shock some people here on FR, but what you describe is exactly the way the U.S. Constitution intended our government to work.
True enough. And of course a Senate controlled by the same party as the President is free to reject the DNI pick of a POTUS under Deep State coupist assault. Given that we can put away any pretense that the current Senate is substantively supportive of President Trump.
Donald Trump isn't a real Republican at all. That's one of the biggest reasons why some of us voted for him. He's the first major presidential candidate in my lifetime who ran a campaign that openly OPPOSED several of the key items in his own political party's national platform.
He's an independent/nationalist operating in a government that is dominated by globalists. You ought to come to grips with that before you get too disappointed.