For an invasion of Taiwan numbers are important, sure, but it's a wide channel and amphibious assaults are absolutely the hardest kind of operation an army can attempt. Technical competence, and I would also argue operational flexibility at every level, are absolutely crucial.
In terms of supply chains, that matters for an extended conflict, as we can see in Ukraine. However an invasion of Taiwan would either work in the first week or so, or it's over. I suppose they could try a long terms blockade, but that doesn't seem to be their strategy.
China is extremely vulnerable to a blockade themselves though. They have no control of their essential seaborn supply routes, and are highly dependent on external sources for energy, raw materials, high tech parts, and maybe most importantly food and fertilisers. The US can turn all of that off like a tap at a moment's notice.
The sorts of sanctions levelled at Russia since last year would have China on it's knees in months. The only way to mitigate that would be for the PLAN to go toe to toe gobally with the US, UK, French and Australian and Japanese Navys all at the same time. Also maybe India. The Indian Navy is small but it's no joke, and they have two fully operational carriers.
He's too absolutist for my tastes, he talks about China 'going away' due to demographics. That's just silly, they'll suffer for sure but 1.4 billion people don't just disappear. Also his line about Russia needing to control geographic access points or 'they're finished' is equally silly. They have nukes.
Peacetime armies are generally bad, but turnover tends to be high when the fighting starts, and the second or third set of generals is often much better.
The most important advantages China has are pretty overwhelming- a giant population, and they own the global supply chain for microchips and batteries, meaning they can replace smart munitions and systems while their opponents can't.
They also have the best setup for doing go it alone, vertical industrial production, much better than the US or Russia. They're fine in any scenario where they don't get totally blitzed in a week.