The ultra rich are desperate to maintain their exclusive access to essentially pay no taxes through their "Buy, Borrow, Die" strategy (if you don't understand what that is you should stop and read this: https://gemini.google.com/share/e230bcecaaeb) and so they are using scare tactics / gaslighting around wealth taxes because a wealth tax would disrupt this essentially zero tax strategy.
"Buy, borrow, die" is a bit of a bogeyman of the Left; it's not a common strategy for HNW or UHNW individuals, and to the extent it is used, there are much better ways to close it than a wealth tax, which is coarse and rife with implementation issues.
There's a federal estate tax of 40%. WA state has an estate tax of 20%.