You said that.
I guess you stopped using MARA?
I said it as an alternative to MARA. if some day I solve one of those low bits puzzle i am going to use MARA but i am going to documented all the process properly.
So, as far as I understand, MARA is the only place that provides this service and its tests are not clear, but it can manage the process best.
Mining your own block and making agreements with other BTC mining pools is a very tedious process.
So, after getting 1 confirmation, can the thief make changes by increasing the fee again?
Example;
I paid 1,000,000 sat fee, I got 1 confirmation in the block. RBF is also disabled.
Then can someone who paid 5 M fee change the transaction?