Regarding ghasts

As almost everyone knows, in minecraft theres an advancement called uneasy aliance...

but what if it wasnt uneasy? what if we let them live? that would be another advancement like "easy aliance" or "welcome home" yknow

Now with this, if we let a ghast for 45 minutes in the overworld, it becomes a happy ghast

Same for happy ghast, if 45 minutes on the nether, it becomes a sad ghast and we can also get another advancement "friends to enemies" or something similar.

it'd be cool tbh to have more detail on ghasts