This. Striking a tone of curiosity helps soften what you're saying, versus creating an accusation that they feel they have to defend against. Ideally, it'll open up the person you're talking to, so they can join in your curiosity and better see in themselves what you are seeing, or at least create more mutual understanding.

Unfortunately, people that are immature and deal with their insecurities poorly this doesn't tend to work on.

At a certain point, people have to want to work on themselves and you have to not concern yourself too much with how they react to information that triggers their cognitive dissonance defenses as long as you are approaching them from a position of empathy and curiosity. It's easy to want to keep helping people no matter what but at this point they will just drag you down to their level as a form of self-protection.

So I think the "solution" (or maybe it's a cop-out?) is that you can nudge people certain ways and expose them to new information, but what they do with it is entirely their responsibility and you have to let go if you make a good effort to communicate and they just aren't receptive. We only have so much emotional energy and should use it wisely.