Some of these posts are months old, but since the OP is still active on the forum, I've got a few things to say.
Is space opera obsolete other than the two big titans of Trek and Wars...
No, of course it isn't.
Ben Bova is still publishing new novels (with a co-writer or possibly a ghostwriter at this point due to his age, but that's just speculation).
C.J. Cherryh is releasing a new novel in her Alliance-Union series next year - and most of that series is very definitely space opera (not sure how to categorize
Forty Thousand in Gehenna,
Cyteen, and
Regenesis since they take place on planets and space travel is just mentioned - albeit in very important contexts such as how to effectively conduct elections and commerce over interstellar distances without FTL communications).
I guess I've always assumed that "space opera" was supposed to be kinda pulpy. That's part of the appeal.
There are different qualities of space opera, though. I've read the
Dumarest of Terra series twice over the years (minus the last novel, which has such an absurdly high price on it on Amazon, that I'll never be able to afford it unless I get lucky at a garage sale and nobody knows what they're letting go for a loonie or two). It's formulaic, there are particular scenes that are obligatory in every novel, somebody usually dies a gruesome death of some sort, there's always a female character who's attracted to Dumarest (sometimes it's mutual), Dumarest runs into the local branch of the Cyclan (the ongoing villains of the series), and so on. I wouldn't call it high quality, and two local librarian acquaintances who helped introduce me to SF conventions scolded me for reading them. But I don't care - they're mental junk food that's enjoyable every few years, and unlike the thousand-page novels I'm reading these days, I can romp through a Dumarest novel in a day or maybe a day and a half. I once timed how long it took to do the 31 books I have, and came in just under a month.
Constrast that with Ben Bova's Grand Tour series... there's a guy on one of my gaming forums whose RL job is literally a rocket scientist. He helps build this stuff, and I asked him how plausible Bova's science was, for exploring the solar system. He said it was reasonably plausible, or at least most of it. A bit more research and a lot more money, and we could actually do some of that stuff, like asteroid mining or research bases on the Moon and Mars - orbital colonies, too.
Want great female characters in a space opera setting? I can't recall how many times I've re-read C.J. Cherryh's novel
Rimrunners. Bet Yeager is one hell of an independent, no-nonsense character.
And of course one of my favorite space opera series is the Hulzein Saga, by F.M. Busby. It's one of the more credible attempts to incorporate relativity into creating a setting where news, commerce, and military maneuvers have to take into account that while the ship crew might experience 8 months, 10-15 years might pass on-planet.
Did Frank Herbert come up with folding space? This is spicier than the two titans for sure. Excuse me but I hope it's a huge tentpole franchise and one that can make it's way to tv like I think it can 'cause it seems to be very contained eventually branching out hopefully into the next sprawling Titan.
Whatever is done about Dune, please let it have nothing to do with Kevin J. Anderson, Brian Herbert, or Byron Merritt (FH's grandson who is basically a nice guy but thinks the nuDune crap is actually good), or any of their nuDune garbage.
It may be confined to this solar system but I think The Expanse must tick a lot of the boxes one would think of for "epic space opera".
There's nothing wrong with being confined to this solar system. Most of Bova's novels are, and there's a British SF show that it seems nobody knows about but me (since I've never found any other people to discuss it with), called
Space Island One. It's about an international group of research scientists who are based on a space station in Earth orbit.