If you go by the default constitutional allocations, Congress starts with much tighter control of how the executive operates than it does now. Via passage of laws, Congress over the years has chosen to delegate a lot of responsibility to the executive branch - some for pragmatic management reasons, but some as a trend of historic concentration of power towards the executive. Congress can also delegate to non exec branch bodies like the Fed and other quasi-govermental orgs. Congress has the constitutional purview to take back a lot of that power into it's direct hands instead of allocating it to other bodies if it so chose.

Isn't that the entire point of congress? Otherwise why not just have an all powerful president and do away with the houses

It wasn't an issue for 250 years, or at least until the Unitary Executive Theory became a dream of the Federalist Society.

I don't understand why you're being downvoted. This sounds like a reasonably debatable argument.