Yeah, there is no way to cancel the transaction when it is already in a pending state. I was also shocked when I came to know about it, actually, I was making transactions before knowing it, but one day my transition for BTC was taking a long, and for the very first time it took around 3 to 4 hours and I was damn worried about the transaction. Then I did some research and came to know about the transaction's states.

Actually, I was already aware of them but did not come to think of them at that time, well, these states are pending, completed, and Revoked which means, that when you have made the transaction, it goes to the pending state and it can not be canceled and after it will be either completed or revoked if found some error by the miner/validators.

It is the same as a transaction which has some database features. This means a transaction in progress can not be reversed or canceled because it would cause so much trouble like the biggest one is getting scammed or doing scams etc. The result is, cancel feature can't be added (AFAIK).