The Article itself stays within the scope of the Executive Branch but the Section itself just says:
The President, Vice President and all civil Officers of the United States, shall be removed from Office on Impeachment for, and Conviction of, Treason, Bribery, or other high Crimes and Misdemeanors.
Likely, if Congress tried, it would be argued that the scope is only the Executive Branch.
Article 3's scope is the Judicial branch but says in Section 1:
The judicial Power of the United States, shall be vested in one supreme Court, and in such inferior Courts as the Congress may from time to time ordain and establish. The Judges, both of the supreme and inferior Courts, shall hold their Offices during good Behaviour, and shall, at stated Times, receive for their Services, a Compensation, which shall not be diminished during their Continuance in Office.
However, Samuel Chase who was appointed as a Supreme Court Justice by George Washington and confirmed by the Senate was impeached by Congress in 1804, and other federal judges (some having life-time appointments apparently) were dissolved.
Samuel Chase ultimately was acquitted by the Senate in 1805 however.
Who would decide tho who can impeach Supreme Court Justice? Because it can't be SCOTUS as that would be deciding in your own case and you guys also don't have a separate constitutional tribunal
Article 2, section 4 clear says "and all civil officers." It specifies president and vice president likely because they were getting away from a monarchy and wanted to specify they aren't above the law, but it clearly should apply to any federal civil officers.
Does this actually matter if the Supreme Court is ruling in the constitutionality of how accountable they are to other's power? Probably not. This supreme court at least will always argue in favor of serving themselves. I don't know how that plays out at that point.
Hell, people in the military just need to go on and execute the offending members of the supreme court, the house, etc., then just say "the president told us to do so".