Oh, the Congress did work during Obama's presidency. They voted to repeal and not replace the ACA something like 50 times. At least now they've come to their senses and realized they have to come up with a viable replacement before they repeal.
Now to be fair most of Trump's executive orders are the standard stuff that most recent presidents have issued early in their terms, although Trump's version on a few have gone farther than previous Republicans'. Several orders like the executive branch hiring freeze are well within a president's powers; some like the muslim ban will likely have to be settled the courts.