Theoretically speaking, can I take my private key and open it in multiple wallets at the same time. For example I would have an Electrum wallet, blockchain wallet, Bitcoin Core, etc...? All wallets would be active at once? So if I send from my Electrum wallet it would be subtracted from the other wallets too?
Never tried that. But it should work in the same way as wallets are just vessel to watch the value of the private keys.