"High crimes and misdemeanors" is a term of art that refers to acts committed by a public official which, while not necessarily a crime in themselves, are a violation of public trust.
For example, a president that accepted a foreign title of nobility without Congressional consent would have committed a high crime, but they couldn't be hauled into a criminal court for it.
The only thing Congress can do is remove Trump's disqualification under the 14th amendment. They can't decide whether he's disqualified in the first place.