The tl;dr here is, with all due respect, that your premises are basically all wrong.
> (1) reducing oil shipments to China is good posturing for the US
No, it isn't. For several reasons:
1. China has stockpiled ~1.4 billion barrels of oil. it'a net importer. Supplies from Russia aren't disrupted. At present, Iranian oil is still gointg to China;
2. China is rapidly decreasing its dependence on fossil fuels with renewable energy projects on a scale where they're building more solar, for example, than the rest of the world combined. They also produce those panels so there's no supply chain risk there;
3. While the US is a net oil exporter, it's not universal. California, for example, has no pipelines so 75% of its oil comes from the sea. ~20-25% of that comes from Iraq and is disrupted by the Strait being closed;
4. Qatar produces 20-30% of the world's Helium supply and ~20% of the world's LNG, both of which are disrupted;
5. ~30% of the world's fertilizer is disrupted by the Strait being closed. The US is way more impacted by fertilizer disruption than China is.
> (2) Iran isn't the only one who can control passage throught the strait. All gulf countries can do so.
The other Gulf states are US client states. Why would Saudi Arabia close the Strait, which especially hurts US interests?
I also doubt any of them can to the same degree. The entire Iranian military is geared towards this strategy with drone and ballistic missile production on a scale no other country is really built for. It has hardened military infrastructure designed for decades to resist US bombardment.
Other Gulf states don't have this hardened infrastructure and are more vulernable to Iranian attack if it came down to it. Take desalination plants as an example. Yes Iran has those too but Iran also has significant snow melt as a source of water, Mountains, remember? Iran has ski resorts they have that much snow.
> Russia invading Ukraine and failing
Russia has basically succeeded. You have fairly stagnant battle lines where neither side can particularly advance but Russia holds certain Ukrainian territory now for years. Russia is just going to wait for the West to get bored and give up. Russia's economy has proven itself to be surprisingly resilient.
Sanctions just don't work on enemies like Iran, Russia or North Korea as well as they do on allies or former allies because enemies have an entire national project to resist American imperialism. They have to be self-reliant in a way that allies just don't.
This is also why the US client states in the Gulf are hurting way more from the Strait being closed: their economies aren't built for it. Iran's is.
> ... the weakened China (due to oil constraints) would be simply unable to attack in 2028, the strategic window when it can do so.
So this is where you've really gone off the deep end. China is less affected by this, in part because of long-term strategy but short-term because Chinese shipments are still going through the Strait.
American imperialists (which is both Republicans and Demorats, for the record) have this weird idea that China will invade Taiwan. Or wants to. Or it can. None of those things are true.
It really feels like projection, like every accusation is a confession. China must be doing violent imperialism because that's what the US is doing.
China can blockade Taiwan but that won't really do anything any more than an aerial bombardment will do anything to Iran. China doesn't have the amphibious capability to land an invasion on Taiwan any more than the US does in Iran. If you think otherwise, I'm sorry but you're gorssly mistaken.
But all of that ignores the real issue: China doesn't need to invade (or blockade) Taiwan. Why? Because all but ~10 countries in the world already view Taiwan as part of China. In the US (and Europe) it's called the One China policy. It is US government policy and consistent across both parties.
Why would China upset the international order when everybody already agrees with them?