"Шістдесят дев'ять гривень"
the ь makes the sound before it softer no matter what so just say but in a gentle way that's how i pronounce it
no, it is another sound, but if you make ть as a sound that is a little softer than ч you will get чь and possibly be understood. One can check the sounds on forvo
I try to pronounce the ь as a very soft j after the letter: i.e. ть is tj and дь is dj.