I mean the method they will use to not expose the pubkey, I am intrigued to know if Mara will be faithful to what they offer.
It is impossible once the transaction started in any case. Transaction should not fail, that's why I explained you must pay high gas prices.
The fee is not important here, and it should not be excessively high either, this would only attract the attention of Mara miners, the important thing is that the Tx is attached to a mined block without being exposed before its confirmation in the mempool.