What would make carrier strike groups effective in the situation? Given their recent record in the defense of Israel and against the Yemeni Red Sea blockade, one could argue that their era is over. The two most likely outcomes from a carrier strike group engaging with China forces are either a humiliating retreat, or WW3. I think US are smart enough to keep them at bay. Maybe station one in the area for monitoring the situation and assisting evacuation of Americans.
You are approaching this from the wrong direction.
Air forces, navies, and drones cannot conquer a country. For that, you need ground forces with plenty of heavy equipment. Which can only cross the sea in slow and vulnerable ships. To stop them, you need long-distance firepower with large enough warheads. A carrier strike group is the least vulnerable way of delivering such firepower.
The job of a carrier strike group would not be defending vulnerable targets, as in Israel or the Red Sea, but destroying them. Its job might not even be engaging the attacking forces. It could be a reserve force beyond the reach of the initial aerial campaign but still close enough to move in when the actual invasion starts. It could even be a force that remains neutral if the actual invasion never comes (unless China attacks it first).
So how will the carrier strike groups be used? Sink Chinese navy ships? That's one step up the escalation ladder.
China will reciprocate with sinking some escort ships of the carrier groups, just to make a point and demonstrate their hypersonics. Another step up the escalation ladder.
At which point, the carrier groups either back off to de-escalate and avoid losing a capital ship. Or stay there and continue the escalation. As mentioned in another comment, this is projected to stop the Chinese invasion at the cost of losing two carriers. That is, if WW3 doesn't start first.
The underlying assumption is that the US intends to escalate to a full-scale war if China does not back off. If China does not believe in that, the US Navy is just a bunch of expensive but inconsequential toys that can be safely ignored.
If the deterrent works and China does not invade due to the risk of a major war, it's the best-case outcome. If it fails and a war breaks out, massive casualties are likely. Wars are usually not as one-sided as the ones the US has fought in the past decades. But it would not be WW3, as most countries have no reasons to get involved.
