Reframing our advice
Most of your advice misses the core. "Stop being envious" or "Get rid of your resentment about that". You could do with a more powerful reframe. For two main reasons, 1) the person you are speaking to makes his/her own decisions and acts on them 2) he/she trust the words in their heads more than the words spoken at them.
A better reframe could be: "the best way to guarantee a life of misery would be to constantly compare yourselves to those who have "more" than you do" or "if you want to ruin your personal relationships and mental health, hold on to tiny problems from the past and never forgive".
You should stop trying to change others and just provide a reframe that might help.