It's not about that at all, though. It's about how no one person is the center of the universe and that everyone, no matter how cool their lives look on the outside, has their own pain and struggle that they are dealing with, and how you shouldn't assume that you are the only one who has problems. A huge part of the overall journey of the film is about the main character learning and realizing that everyone, even the most perfect-seeming and special members of her family, experiences struggles and suffering, and that she isn't actually the only person with problems. It's about how you shouldn't assume that just because someone looks like they have a fabulous, perfect life that they don't have shit they're dealing with.
Basically... it is about trauma and empathy, not in a "you should forgive your bully right now because they're going through some shit" kind of way, but in a "you aren't the main character of the video game called Life and you should recognize that other people have problems and suffer just like you do, no matter how awesome their lives look on the outside" kind of way. It's got a nice side of "don't make assumptions about people, you don't know what's going on in their lives." And it's also about how family and community matters, and how people can come together to solve problems and heal wounds that they couldn't do on their own. It's a really positive, healthy message, especially in our incredibly individualistic world.
Also, Bruno wasn't exiled by his mother and forced to live in the walls. He did that by his own choice in order to protect his niece, Mirabel. He was afraid that his family would turn against her if they knew she was in one of his terribad visions of the future (because of the assumptions they made about him and his visions - another way the film shows that making assumptions is bad!), so he fled and lived in the walls so no one would find out about the vision he had. He comes back in the end and all is forgiven because his family has (emotionally) grown enough that he doesn't have to be afraid of the consequences of his visions anymore.
Finally, I'll note that the movie emphatically doesn't end with everyone acting like "nothing happened". The end of the movie is about the family recognizing what they had done wrong in the past, recognizing each others' suffering, and coming together to rebuild stronger with all that they have learned over the course of the film (and their lives). The whole point is that everything happened and they've learned from it and become closer and stronger and better for it.
(Disclaimer: Not a "Disney Person" really, saw Encanto on Christmas because it was free and really liked it.)