I feel like I wrote this post from time to time on Reddit and I think I'll start this tradition here. I'm. a Honor Harrington fan. I've read several other space operas and they always fall short. The three that came close were Lt. Leary, Kris Longknife and Vorkosigan saga. Lt. Leary was nice, but it failed on World building. Kris Longknife also failed on world building and had astronomical levels of cringe with aliens and plot, but I enjoyed it. Vorkosigan saga had better world building and it was nice overall, but the books without Miles Vorkosigan weren't enjoyable. There were other series that I enjoyed: Serrano Legacy, Vatta's War (those are some of my favorites but they were too short), Starship's mage (it declines with every new book), The Lost Fleet (it has a serious plot problem, the plot doesn't move forward), Old Man's War (it was really nice), Dread Empire Fall (also awesome), Teixcalaan (good, but short), Alarm of War (good, but short and pretty generic), Bobbiverse (I read until book 3, it isn't for me), Red Rising 1st trilogy (really nice, but too Hunger Gamish, this whole dividing society into a cast system is getting old), Ark Royal. The Three Body Problem was awesome and, contrary to most series, didn't leave me craving more after it was over. Edit: forgot to mention The Expanse, it was OK.
I think that what won me over on HH was the fact that she is a complete Mary Sue and other character don't fall far from the tree, there is a nice world building, characters die, and there is a ton of action.
On the other hand, there are some long books that I enjoy that aren't space operas. I really enjoy the Dresden Files (because he is cool and it is a long series), I absolutely love Jack Reacher (it is just a nice fun read, it's like a nice Big Mac), I also enjoy The Spellmonger series, and I enjoyed the Riyria. I disliked Takeshi Kovacs (lack of sequence and plot) and I absolutely hate Southern Reach (VanderMeer), and there is another popular sci-fi book that is written as a report, which I also hated. I don't like those very innovative mystery stories where you are trying to figure out wtf is going on or waiting for a plot to start until the middle of the book.
Got any suggestions? =)
(OMG, after writing this post, I see myself as an incredible hard reader to please)
Even if you don't think you're into Warhammer 40k you should check out the books. There's 100's of them and are actually very good. I put them off for a long time because i thought they'd just be battle porn. They are well written with compelling narratives, great characters, a sprawling galaxy full of different aliens and factions, and of course the aforementioned war porn.
If you are hesitant like i was, i recommend starting with the first three books in the Horrus Heresy. There's like 40 something of them but the first three you could read and put down satisfied without continuing if you wanted.
I always list the three books out for people because there's so many it's easy to get lost looking for them.
Horrus Rising, False Gods, Galaxy in Flames
As for a non-opera book, I highly recommend Seven Eves. I don't think i saw it in your post. But you had a long list so forgive me if i missed it. It's one book, pretty long though and one of my GOATS.
I second this. I've never played or painted, but I'm fascinated by the universe, and it is LONG. I'm just now finishing the prequel series (the Horus Heresy) which is over 50 books long (and some extra short stories). The main universe has 500 or something books.
I listen to audiobooks on the way to work, and used to do the same on the way to school, so I go through books very quickly.
I started reading the Gaunt's Ghosts series of books (I found a recommendation on some 40K subreddit a few years back). Some of them are really interesting with politics and (fantasy) tactics. Others are artificially bleak and evil, which lead me to stop. At one point it felt like the author had started retconning a minor character to be some crazy evil murderer, almost as if the publisher went "needs more bleak", and it really boiled my gills. I didn't feel like this character did anything other than cause random unhappiness and excuses to kill off characters; at no point did it tie into the plot or serve any proper purpose.
Oh and these books are stupidly expensive to get even second hand. I've also never succeeded at finding any in charity shops. For some honest and innocent reason my copies seem to have very bad OCR, but you get used to it.