It is basically one confirmation is enough as Bitcoin transactions are irreversible but depends on a transaction value, there are different recommended confirmations to make sure that your deal is done and settled deeply in Bitcoin blockchain.
Right, but that's something else. I was trying to explain to the OP that even a seemingly perfectly timed transaction entering the mempools can require longer waiting times if the time between two mined blocks is too long. You might be required to wait even longer if other transactions are sent, paying a higher fee than you initially did.
What i just understand is that if there is so much congestion in the mempool, your transaction is likely to attract higher fees and if you try to adjust the fees it means it will take longer for your transaction to be confirmed.
If you perform a RBF, you increase the network fees, giving miners more incentive to include your transaction in their blocks.
People are generally too worried if their transactions don't confirm quickly. I don't know why that is. If it's not time sensitive, just leave the transaction alone and it will confirm eventually. I have had transactions sitting in mempools for a week. You are not going to lose the coins. They will either reach the destination or come back to your address.
If the transaction you are sending is time sensitive, pay the high priority fee and even above it to put it in the best possible position for a quick confirmation.