I won't disagree with you that the Executive has to have power to administer what Congress orders (e.g. when Congress approves funds for something, the Executive has to make that happen). That's not what the Felon is doing.

It's not all he's doing, but it's a lot of what he's doing. Sure, some of the things he's trying - like violating the anti-impoundment act - are deliberate efforts to flount Congressional control. So too his efforts to get all the independent agencies abolished or under his control (though at least there he's mostly going to court).

But much of the stuff he's doing is just using the tools that Congress gave him, just in a very different way than all his predecessors. Congress created a shirt-ton of federal programs that required a shirt-ton of people to implement them... which meant they had to give the President the power to direct their activities and hire and fire them. Which is how DOGE happened. Congress sends massive amounts of money through the Executive to fund all kinds of programs - and since Congress can't possibly review every grant application and project proposal, they had to give the President the authority to do those reviews. Which is how all the pressure on colleges happened. Etc.

Congress relied on the fact that most Presidents need to have a working relationship with Congress in order to do the things they have on their agenda. So they would pick agency heads that would (and could) work with Congress, allow their agency employees to respond to Congressional interests, and make sure they weren't goring any oxen that might have connections with Congress. Trump doesn't care. At all.

So he has entirely changed the dynamic of the federal government. No one is allowed to be solicitous of Congress or outside constituencies. Every action has to be advancing the President's policy goals, and no one else's. He's able to do this because he's ordered everyone in the government to do this. No more leeway for staff to decide on their own between priorities, no more discretion to appease a budget committee chair... and no political consequences for staff anymore for not caring about Congress or outside interests, because everyone knows that these are all Trump's calls. Trump takes all the political heat (which he can handle), so he makes all the calls and everyone can pound sand.