I did read the lyrics. There is definitely anger there but it feels like more of a defeated kind of anger. When she sings about how the other person wronged her, the tone is kind of like “well you won”. It reads not like she was leaving him outright, but that she was forced to back away.
you’re right, although i interpret it more as a sadness of realization that she couldn’t be her best self while with the other person.
i think also i feel this way because every version i’ve heard before including the original r sung in a more somber way. i think serenity’s approach is reasonable given the lyrics but just felt a little jarring