I'll plug some excellent work that is underrepresented here:
CJ Cherryh's "Cyteen". Won the Hugo for best novel in '89. The backdrop is Cherryh's Alliance-Union universe -- which is arguably one of those classic "cold war in space" type space opera settings of science fiction of a certain vintage -- but that conflict isn't the focus of this novel. Cyteen is set in the research organisation that designs, grows and conditions the "azi" clone slave caste that generates population of labourers and specialists required to keep the Union society running. I found it initially slow going, but it turned out to be one of the best novels I've read in a long time. The plot is a kind of coming-of-age / political-intrigue / murder mystery tale. Not a space opera - power games, paranoia, abuse. https://en.wikipedia.org/wiki/Cyteen
Yoon Ha Lee's "Ninefox Gambit" (first of a trilogy, each book in the trilogy shortlisted for Hugo best novel 2017/2018/2019). Space opera / military sci-fi. The political stability of the empire depends upon adherence to the empire's standard 'calendar', which is maintained through ritual torture of heretics. Much exotic technology depends upon calendric properties, and fails in regions where populations are following a nonstandard heretical calendar. The outcomes of battles depend not only on how many fleets or waves of infantry can be expended, but each side's mathematical ability to understand the local calendrical properties and adapt their tactics and technology accordingly. The plot follows a military officer's mission to quash a rebellion at a key star fortress -- and her attempt to improve the chances of success by having the mind of a dead undefeated war-criminal general loaded into her head. Space opera / military sci-fi.
Arkady Martine's "A Memory Called Empire" (won Hugo best novel in 2020). A tiny independent station sends a replacement diplomat into the heart of a neighboring empire, in an attempt to direct the empire's attention elsewhere and maintain independent station sovereignty, and discover what happened to the previous diplomat. Backdrop is suitable for a space opera, the story is political intrigue. The station society is one where memories and personalities can be artificially recorded and stored, and then re-implanted into future generations to preserve skills and knowledge. The novel explores attraction and intoxication with the culture and language of a dominant foreign power that is threatening to engulf one's own home.