A surprise intermission for Some Constitutional Amendments
Aside from your points at the bottom, I think there needs to be one more section here: the Republican and Democratic Primaries. These specific two parties have been around for long enough without serious challenge lasting more than one cycle that they're an inherent part of how things actually work. (Which's a bad thing, but nowadays I'm leaning toward such stability being baked into our modern quasi-Jacksonian party system combined with the size of the country.) Also, the popular primary system has shifted a lot of power out of the executive committees. Nowadays, it would be thought illegitimate for committees or "superdelegates" to actually choose a candidate.
Also, yay Space Force! If it only involved actually sending people into space!
In Article I, Section 6 you omitted the paragraph:
"In addition to compensation and expenses, Representatives and Senators shall be entitled to trade shares of public or private corporations without limitation, including acting on, or in response to, non-public or inside information they may be exposed to, officially in the conduct of their ordinary business, or unofficially by any means otherwise. Congress shall have the sole authority to limit the income potential of its members in this fashion. We expect they shall never exercise this authority."
I don't know whether to laugh or cry. Maybe both.