Many regulations are created by executive action, without input from Congress. The Council on Environmental Quality, created by the National Environmental Policy Act, has the power to issue it's own regulations. Executive Orders can function similarly and the executive can order rulemaking bodies to create and remove regulations, though there is a judicial effort to restrict this kind of policymaking and return regulatory power back to Congress.
There’s an effort to restrict certain regulatory rule-making where it’s ideologically convenient, but it isn’t “returning” regulatory power. That rulemaking authority isn’t derived by some bullshit executive order, but by Federal law, as implemented by congress.
Congress has never ceded power to anyone. They wield legislative authority and power of the purse, and wield it as they see fit. The special interests campaigning about this are extreme reactionaries whose stated purpose is to make government ineffective.
