A "soft" way of saying dat da referred-to individual is a crooked a**h**e who doesn't give a you-know-what about honestly or integrity, or about how his shamelessly-self-serving actions might harm fellow humans or da environment/economy in general.
Examples of public figures who turned out to be "of modest morals" would be "Tricky Dicky" with Watergate, and Kellyanne Conway with her infamous "alternative facts" claim.
Ultra-modesty is modesty that is taken to more extreme than usual levels. Ultra-modesty is often used to describe women in relationships who devote themselves to their partner/future partner in ways that others may view as extreme. Such examples of this include not posting on social media, not talking to other people, dressing extremely modest, and hiding their face.
Person 1: I can't believe Person 3 stopped talking to us.
Person 2: She got a boyfriend and decided to be ultra-modest for him.
Person 1: I respect that. Ultra-modesty sounds like true love!