It's time to scrap the whole thing and go Parliamentary.
Here I disagree. Current system is well-balanced and needs some modifications realized in amendments. Actually I admire US political system. Consider it the best in the world as can compare with systems in other countries.
I would argue that we already operate as a de facto parliamentary republic. The Executive Branch is the Government. It sets policy through executive orders and regulations. Congress has been relegated to the back bench: necessary for major changes, but it's given up its role as the primary originator of policy. Ben Sasse gave a speech in the Kavanaugh hearings expressing exactly this. It's been going on since the 1930s.
Unfortunately, the President answers to no one except the American people, and then only once: when up for re-election. So we now have the worst of both worlds.
At this point, placing the cabinet under direct control of Congress would return some power to the people. We are teetering on the brink of autocracy, just like what has become of many states modeled after our Constitution.