I am looking for a security method when finding a puzzle for a transfer to another Bitcoin wallet!

How to Claim your BTC Reward?

1. Which Electrum version should you use?
1.1 With RBF Off, should it be safe right?

2. Should you sign the transaction?
2.1 How high should you set the salt for the transfer?

3. How can you bypass Mempool the transfer there not appear that the bots do not crack the public key and use a big salt?

Thank you
I look forward to further suggestions!