The charge of high crimes and misdemeanors covers allegations of misconduct The charge of high crimes and misdemeanors covers allegations of misconduct peculiar to officials, such as perjury of oath, abuse of authority, bribery, intimidation, misuse of assets, failure to supervise, dereliction of duty, unbecoming conduct, and refusal to obey a lawful order.” to officials, such asperjury of oath, abuse of authority, bribery, intimidation, misuse of assets, failure to supervise, dereliction of duty, unbecoming conduct, and refusal to obey a lawful order.”
You are correct that Trump's tiff with North Korea wouldn't fall under the above stipulations, but just as the feds got Al Capone for tax evasion rather than his other more horrific crimes, I'm sure that the Republicans can find some other reason to get rid of him by impeachment. God knows, he's given them many choices to select from.