If you are saying an on-chain (layer 1) instant transaction, we don't know, since the Bitcoin developer implemented and is still improving an off-chain instant transaction like the Lightning Network.  I think with this trend, Bitcoin developers do not want to tamper with the 10-minute block confirmation of Bitcoin. 

We have an off-chain solution to settle instant transactions that is already available, but an on-chain instant confirmation of transactions, although possible by tweaking the code of the Bitcoin core program, is dependent on the judgment and decision of the Bitcoin developer.  Whether the on-chain instant confirmation can be implemented or not is for us to see.