Yes, theoretically, the EPA could be reined in or abolished, through legislation by Congress, and signed into law by a president.
These unelected liberal EPA bureaucrats have way too much power. The EPA, and all government agencies, serve under the President and Congress, not the other way around. Elected officials are supposed to tell them what to do, not the other way around.
Yes, Congress and a President can override anything the EPA does. Whether the political will is there to do so remains to be seen.
Congress is so "bought and paid for" they very seldom, if ever, work FOR the citizens of the Country.