@bob123 you are completely right, I immediatly installed samourai for future transactions.
Samourai definitely is a good choice.
Only to afterwards see that RBF is disabled and fee control is barely there they give you 3 options only and these options wouldn't even tell you how much sat/b the fee's are
But that's weird. If it promotes having RBF, then there might be an option somewhere? But nonetheless.. only offering to choose between 3 options for a fee is incredibly bad.
Samourai is definitely the better choice here.
Can I ask something since you already mention this. I notice that Electrum Mobile Wallet is giving an option about replaceable transaction. Is this the same stuff that can make the user change the transaction fee for the existing transaction?
*I always choose no on that option because I thought that I might commit double spend if send again another transaction while the first transaction is still unconfirmed.
Yes, this setting is exactly that, enabling Replace-By-Fee (RBF).
Well, it actually is a double spend. But by using the "bump fee" feature, you are double-spending the same UTXO in a new transaction to the same recipient. Just with a higher fee.
It could be exploited to make a double-spend sending the funds to yourself. And that's the reason no one should accept 0-conf transactions. Especially if the RBF flag is set.
There is rarely any use case where RBF does harm you. Close to no one accepts 0-conf transactions. And after the 1st confirmation, the RBF flag gets "useless". The TX can only be replaced while it is unconfirmed.
You don't need to worry enabling that feature