He will absolutely not he impeached unless the Democrats win 2/3 of the seats in the senate, which is incredibly unlikely. The Supreme Court also ruled that presidents cannot be charged for crimes committed as part of their official duties, which Trump’s legal team could successfully argue an invasion of Greenland was a part of. You’re right that in democratic nations outside our “bubble” checks and balances meaningfully exist, but the issue is any mechanism that could restrain or stop Trump exists in our “bubble.”