There have been frequent and repeated comments by Trump about "annexing" or "absorbing" or taking over other sovereign countries.

NY Times How 51st State talk became seen as deadly serious

White House Asked US Military for Panama Options

CNBC - Trump on US Annexation of Greenland

I think anyone paying attention to this should be extremely alarmed, especially when you connect this to the purges that he is doing to the US military and other organizations that would limit the power of the president, and of course recent supreme court rulings about presidential power.

It appears like he's trying to get people used to a new colonialism. Maybe if he attacks Panama and there isn't much internal resistance, then he'll attack Greenland, and so on. Sure we can guess whether he is doing this to help Putin, or to normalize Putin's invasion. In any case just the discussion of these things harms the other countries, the reputation of the US, and world stability.

Frankly I think this stuff, and the attack on federal workers and social programs and social security, is an attempt to not only do these things, but to generate mass protests which will be used as an excuse for martial law and the removal of other rights, including future elections.

Here's another article, This is by David Frum about how we allow people to minimize Trump's actions at our peril: The MAGA-Strategy Spin Machine

I don't think it's possible to overreact to this. A functioning US Congress would remove him from office right away.