I've not heard of him, no. Incidentally I'll just say, YouTube can be a great catalyst for further exploration or piquing your interest. It is most definitely 'not' a substitute for learning about the topic. Here's a 'much' more reputable source that's worth listening to (though still imperfect IMO):

https://mega.nz/folder/MYlFwYpC#ZHmrbskzPgKHq9BGuWjvFg

Keen's probably the world's leading Post-Keynesian, heterodox economist. His podcast only became free recently and has since moved the newer episodes here:

https://debunkingeconomics.com/

But to the point about a wealth tax. A wealth tax would be incredibly destructive to the US economy.

I'm glossing over a 'lot' of the structuring aspects, but here are some basic mechanics describing what would happen. Incidentally, several estimates of the wealth tax experiences in Sweden, Spain and a few other countries have been done. What's notable about all of these wealth taxes were that they were very small and very 'leaky' in that the wealth they taxed was very narrow (Switzerland is a great example, they barely have a wealth tax because its so leaky, but people love to hold it up as an example, despite it not working for the longest time).

As far as some of the structuring aspects go, private companies are frequently fully/partially exempted from wealth taxes. Well guess what you see a lot of public companies go private post wealth taxes. Is this classified as avoidance? This biggest point here is that none of the economies that have had wealth taxes have as deeply developed finance markets as the US (and yes, that includes Switzerland). Here's an example that some people might understand, and this is hugely simplified.

I have a $100M building outright that I rent to tenants (say an office building). It's illiquid with a thin market and I can't just move a building. Let's say I do this: I enter into a terminally settled, non-transferable, future-callable, sale-leaseback with a partial-repo feature, with an overseas bank. The mechanics are this: I 'sell' the building to, say, Nomura in Japan. This is the 'sale', but I don't take the cash. Instead, Nomura agrees to a 99-year lease where I can operate the and the rent payments are settled via the sale proceeds I never received (this is the terminally settled part). I rent to tenants and keep the net operating profit. Now depending on the corporate profit rate versus the income tax rate, I'm going to either 1) pay myself a 'salary' that zeros the corporate profit or 2) dividend myself, which ever is cheaper. 'Future-callable' means I can undo this in the future; 'repoed' means that if I need some of the money that Nomura is holding from the proceeds, I can get it back in part.

You say, "but the operating lease has value!," but does it really? Its non-transferable, so it has no market value, and I can zero the economics of it so it has no model value; you can't value that using any generally accepted measure. There are some detailed complicating factors in this example, but they can be sorted out; importantly, transactions like this are fairly common for (completely legal) reasons. The main thing I have done is taken the building out of my calculation of 'wealth'. I would have owed 6% times $100M, but now I don't 'have' a $100M building to tax. Nomura has the building. I will owe either income tax or corp tax, but I would have owed that anyway. At any rate, the wealth tax was brought to zero.

You might say "well just make X illegal!" Fine. But tax cases like that can take 10-20 years to sort out, and the goal here is to $0 the taxes long enough that you get the wealth tax repealed. And it will get repealed. Not because of something like "the evil republicans", but because it causes 'massive' wealth distortions that you will pay for. In the extreme it will cause capital flight that will be similar to the stagflation in the 1970s. This was the exact reason that France and Sweden repealed their wealth taxes. it wasn't because rich people left the countries (although some of them did), it was because rich people sent their capital overseas, which seriously jacked up interest rates and capital formation.