Can you make it easier to unbind enter key

To the exact answer of your title of whether they can do it or not, yes it is technologically possible.

When they will implement self mute is another question.

Riot has hinted (if not outright said) that they are not going to implement any further features making it easier to not communicate.

While it's true Riot would prefer you not use chat to you being toxic, they immensely prefer you using chat appropriately to both of those options.

Why do you need to unbind it?

How often to you hit your keypad asterisk key or your page up key? Not often?

Just use the enter key that often.... it's not that hard.

If I don't have something nice or valuable to say, I don't say anything at all.