I disagree, either there is something muted or not. If you would like a feature like that, then I would suggest adding a global option "Keywords override mute settings for conversation".

adding a global option "Keywords override mute settings for conversation".

I meant it as an option (like the above), sorry for not making it more obvious.

There were two possibilities here:

1. add a global option
2. add per chat option

so I prefer to have the first one to introduce less confusing UI.

I'd say that (2) doesn't make much sense so (1) seems like the only option.