I may discover differently as I read the rest of them, but my memory is that the Alastor books by Jack Vance are perhaps the least "series-y" of his many series - a sequence of three books set in the same stellar cluster that I think are basically separate novels connected by the involvement of the head of the government of this vast and vague nation.
Trullion: Alastor 2262 was the first of the three, originally published in 1973 as a serial in Amazing and then as a Ballantine paperback. Alastor is "a whorl of thirty thousand live stars in an irregular volume twenty to thirty light-years in diameter," with about five trillion people on about three thousand inhabited planets, all loosely ruled by the Connatic, whose succession mechanism is not describes but sounds vaguely hereditary. Like many Vance universes, pirates are a problem - here they are called starmenters and are hunted down zealously but still manage to attack and despoil settlements on random worlds fairly regularly.
The Connatic is a minor character here; I think he appears in all three books and affects the action somewhat. But the story of Trullion is about one family on the bucolic planet of that name, where the land is fertile and the people mostly indolent and happy because of it. That family had three sons: one older, and then twins. One of the twins, Glinnes Hulden, went to space to join the armed forces, the Whelm: the story proper begins when he returns, having resigned after ten years soon after learning of the death of his father Jut.
He returns to find that his older brother Shira is also missing - Trullion has a native race, the merlings, who live underwater and have a long-running low-level conflict with humans; both sides kill individuals when they get the chance, and everyone assumes Shira fell victim to them. Glinnes is the older twin, so inherits the land, but his melancholy twin Glay has sold off half of the land as part of his joining a burgeoning movement of ascetics called Fanscherade.
If, or once, Shira is proved dead, Glinnes will be Squire of Rabendary, and is basically that in any case. But he wants to reclaim the lands Glay sold to a newcomer, and is stymied by Glay's recalcitrance and the fact that Glay has already given the money to his Fanscherade comrades.
The plot ambles from there, mostly focusing on Glinnes's new career as a player of hussade, a team game something like a gang version of the much later TV show Wipeout - played on walkways and trapezes above a tank of water, involving padded sticks with which they whack each other - as he tries to get the money to reclaim his lands. Meanwhile, somewhat in the background, Fanscherade is growing among the youth of Trullion - in a permissive society like this, the young rebel by becoming strict and rule-bound - and the racial sub-group Trevanyi (Gypsy-coded: secretive, clannish, nomadic, prone to schemes which may turn violent) are also causing some friction, particularly one group near Glinnes.
There are local aristocrats who sponsor hussade teams, not always well. There's a locally-famous man, Janno Akadie, who works as a mentor, something like a combination of independent arbitrator, lawyer in an advisory role, and notary. There are conflicts with a group of Trevanyi squatting on Glinnes's land.
There are a lot of hussade games detailed, as Glinnes plays on first one team under a local aristocrat who over-estimates his own skill as a captain, and then for a better open team. We learn most of the rules of that game, including the role of the shierl, a young woman - proverbially virgin, though Trullion society makes this reader cast some doubts - who is a "member" of each team, as essentially the goal-posts. (The cover above shows a shierl in a decent indication of her game costume - that white dress is designed to come off at a tug on the gold ring, and that moment is the standard ending of most games.)
All of that comes together near the end, with a starmenter attack during a major
hussade game. Glinnes learns the truth of his brother's death, reclaims his land, and may have found a woman to share his life at the end of this short novel.
One of the things I appreciated here is that Glinnes is fairly ordinary: he's good at hussade, but as a position player. He's not the captain, not the top scorer, not some magnificent master. He's fairly smart and skilled from ten years in the Whelm, but he makes mistakes, misunderstands things, and is the hero of this book mostly because the book focuses on him. He doesn't track down the starmenters; he doesn't save the world; he doesn't even have anything to do with a major conflict between Trevanyi and Fanscherade near the climax. Trullion is his story, which means it's all about things that are important to him - but he's not important, other than being locally famous as a good player at a popular sport and owner of a major piece of land. For a series of books about a society of five trillion people on three thousand planets, that's about right, and entirely appropriate.
Note: I read this in the omnibus Alastor, which has all three novels. Trullion is also available separately, published by the Vance Integral Edition. Either way is fine, but, for me, I'll always pick the larger package.