if I spend some input in a tx and a few seconds later spends the same input with other inputs in another tx with higher fees. If the first tx is still in the mempool would the 2nd tx replace the first one?
With a hot wallet I can receive a notification on my phone every time an input is spent and if I reply to the notification (somehow wallet has been compromised) then I could broadcast a signed tx with all my inputs to another address I control with higher fees. I could potentially outbid the hacker and save the wallet?