I agree! Actually, the whole show kind of disproves Kant's attempt to base ethics on universal laws and reasonable choices. What actually helps Eleanor and the others become better people is:
1/ The recognition that being kind to others feels good for us as well. That we do not have to lose something by being kind, at the opposite we gain. Being kind makes us feel good, nourishes our soul, builds trust in others, and better relationships, and good relationships make us happy. I believe recognizing the connection between being kind and our own well-being is the first step.
2/ Facing the reasons why we are unkind, AKA our trauma, so therapy and personal growth basically. At the end of the show, it is what all people who die have to do to get to The Good Place. Healing, growth, and learning that being kind rules.
Not to ramble about the good place but do you ever think about that bit in season 1 where Chidi sarcastically says "do I also need to tell you not to throw sand" and Eleanor responds with "throwing sand is an excellent way to put out a vodka fire" and how that sums up Chidi's character arc so well as well as challenging moral positions like Kant's that claim that there is one exact solution to any given moment because yes, we would all immediately consider throwing sand to be bad, but sometimes it is Genuinely useful and good to throw sand and to apply the ideology of "throwing sand is bad" to Every situation will be to die in a vodka fire.