Since GPU farm is worthless, 71 has almost no chances of being solved this year. Maybe in next years, unless someone is very lucky or the price goes to 200k.
And about withdrawing the funds. Mara is the only option right now, either you trust it or not.
Once a transaction is confirmed by a miner, there should be no more funds in the source address that a bot or anyone else can resend at a higher fee, right?
This question actually makes a lot of sense because if we use a fee of 0.10014251 and withdraw 7 BTC to the new wallet, then why not use the mempool even with 71? Funds = 0 so there is no more than 1 RBF