It's astonishing how TSMC is the only company in the world that can do this. They are just so far ahead of everyone else in manufacturing. It'd sure be nice to have more capacity.
The Economist had a good article a few months ago about the volume of chip manufacture by country and process size. The takeaway is Taiwan leads < 10nm, the US and Taiwan lead 10-22nm, and that > 22nm is an interesting mix including South Korea and China.
I'm not an expert on the tech and can't say. Just going on what the Economist article talks about, South Korean manufacturing represents a tiny fraction of the smallest processes right now. The article you linked says the 3nm will start producing in 2024. That's good news, maybe there's competition coming.
The Samnsung 3nm will be sold in 2024, produced in 2023. I'll admit TSMC might have an edge in the timing but the OP article also hedges their statements by specifying TSMC will have limited availability of the 3nm in the second half of 2023 and the Apple product refresh in Fall 2023 might contain these 3nm components.
I just don't think Samsung is really that far behind as right now both companies are just selling promises.
Samsung's 4nm was substantially less advanced than TSMC's 4nm (compare Qualcomm's Snapdragon 8 Gen 1 to 8+ Gen 1 when they switched to TSMC). The same is plausible for 3 nm.
It's weird to think we're dependent on single companies for such important things.