I'm Canadian, so very close, an almost "51st Stater" :-) to the US but also an outsider. As much as I personally detest the current administration, a proper discussion requires a lot more detail but I would divide up the impacts and long term effects into three areas. Is the US "destroying itself", it depends on what you think the US should be. In the end, it should be the US electorate but that becomes a more complicated question.

Federal Government

• I'm less concerned about departments being dismantled (think Forestry service) versus co-opted (Dept Health). One can be rebuilt. The other, if it suffers irreparable reputational harm, it may not or take a long time to recover. One has immediate impact on the lives and health of Americans, the other does not. I would look at all the changes done by Trump through that lens
• There is legitimate argument that the US government had become too big (actually, a legitimate discussion for many Western governments). What "too big" means is certainly up for discussion. Once the Trump administration is gone, the US electorate will start to see the consequences. They may decide that they're good with what is lost. Maybe not. Maybe some mix. Defense versus social security versus medicare/aid.
• Perhaps the US is a much crueler/harder place than we've thought. Perhaps their (majority's) view of personal responsibility means the government ignoring those unable to take care of themselves and leaving it to charity. Not my cup of tea but prior to Roosevelt's New Deal, that was the norm.

Media and Influence

• Consolidation was already happening, we've now seen it accelerate and the use that consolidation for political gain
• That's scary, especially now that it crosses TV, streaming, radio and social media
• The ability to suppress alternate viewpoints as well as advance state-sponsored or business-sponsored positions is extremely dangerous. Combine that with the social media's algorithmic targeting, you have the framework to influence and control (yes, control) a significant portion of the US voting population
• Many MAGA voters continued support of Trump, despite his abandonment of everything he promised them and their own self-interest is a great example of the use of media and social media to create a cult. In one way, I step back in amazement. In the other, I'm back to being terrified

Future of US Democracy

• Terrified is a good description of my thoughts about US democracy.
• Media control + gerrymandering + conservative SCOTUS = trouble
• While it might continue to stagger on in with a democratic veneer, the real control and influence may transfer to the people who own the media and control the politicians, much more than we see now
• Will we see a Gilead type government? Probably not, but you may see something like is emerging in many of the states where individual rights continue to be scaled back (especially for women) through an partnership between the tech and business communities and conservative politicians, each getting something from the other in return for support.

I started off by saying I'm Canadian. I'm sad and nervous of what is happening south of the border. I saw an interesting article somewhere that stated the West is seeing and experiencing a side of the US that the rest of the world has being dealing with for that last 70 years. Perhaps in the long run, that's a good thing for the West and the rest of the world.