Jeff Bezos may be one of the biggest landowners in the US, but the cause and effect is backwards. He became rich off of something that didn't need much land (Amazon), and then later bought land with the money. But suppose he hadn't. Suppose he had been willing to just sit on his billions in Amazon stock. Should he escape the tax because he didn't buy land?
There's no way to hide property? There's not much way to hide stock ownership, either. (I agree that you can hide ownership of gold, diamonds, works of art, and bitcoin. But, frankly, not many people are using those as their primary stores of wealth.)
A wealth tax creates deadweight loss, whereas a land value tax benefits the economy? You need an argument to demonstrate that rather than just asserting it, at least if you want to actually convince anybody. From where I sit, it looks to me like a land value tax is just another kind of wealth tax, and is no more or less a deadweight loss than any other kind of wealth tax.
In fact, a wealth tax on stock might make stocks' values correspond more with their dividend rates. That might re-value things like Uber (valued at $90 billion but losing money hand over fist), which one could argue is a good thing. I could see that working in much the same way as you think a land value tax will work for real estate.
