The Vorkosigan Saga by Bujold is considered to be some of the best space opera in the entire genre, definitely recommend giving it a try. Start with Warriors Apprentice if Shards of Honor isn’t to your liking.

This might be the first time I’ve ever seen Starship Troopers defined as space opera, it pretty much kickstarted the military scifi genre.

I’ve been slowly working my way through Stargate, midway through season 3 right now. It’s almost refreshing how shamelessly they reuse old Star Trek plots and tropes, but it kind of works because the show doesn’t seem to take itself as seriously as Star Trek does either.