Is staking now completely banned in the US? What about Cardano and the STI pools?
In short, as long as you own the coins yourself, as with Cardano staking, it is currently legal.
As soon as you give your coins "out of hand", e.g. to an exchange or a provider, it is illegal in the USA. Currently, Kraken is affected by this. However, this should soon affect all providers in the USA. Not only Exchanges.
If you delegate ADA from your own wallet or run your own pool with Cardano, it is legal. With ETH you would have to run your own validator, which costs at least 32 ETH.