The difference between V5 and V20 is very substantial, they're basically the same group in name only.
The Sabbat evolved a lot over the course of the editions of the game from 1st to Revised. They were originally portrayed as a bloodthirsty group of vampire supremacists, mostly shovelheads (i.e. mass embraced neonates), completely ignoring Humanity, and meant to be antagonists to the player characters. But as the editions went on, they started to pick up a lot more characterization. Writers started asking questions like "why would someone see the vampire curse as something to be superior over? How do they justify that? If they ignore Humanity, how do they avoid Wassail?"
In 2nd edition and a bit in Revised, we got some excellent books focusing on the Sabbat, which assumed that players would be playing as them, MontrƩal by Night and Mexico City by Night being the most well known. In these, we started to see a very different view of the Sabbat. They're still vampire supremacists, but their reasoning has changed. They worship Caine and hate the Antediluvians, believing (correctly) that most Antediluvians are tyrants that control their progeny through the blood, and believe (again, correctly) that the Antediluvians are going to be back eventually and they need to be ready to fight them or else be enslaved or eaten. They loathe the Masquerade and the Traditions, believing them to be tools of elder vampires to keep neonates under control. They believe embracing their own vampiric condition is they only way to stay free, and refuse to change their behavior to benefit mortals because, after all, the worst thing that can happen to a mortal is dying, but the worst thing that can happen to a vampire is having your soul devoured by a hungry elder.
Along with this, we see the Paths of Enlightenment, the myriad vampiric philosophies that the Sabbat came up with to replace Humanity, many of which are continuations of earlier Roads from the Dark Ages setting. We see some very monstrous and scary Paths like the Path of Night, embracing oneself as an agent sent by God to remind mortals to fear sin, or the Path of Caine, fanatically worshiping Caine and willing to kill or diablerize others to be a stronger soldier for him. Then there's Paths like Power and the Inner Voice, about mastering the hierarchy of Cainite society, or the Path of the Beast, about seeing yourself as a non-human predator, not necessarily evil and not killing for sport or fun but only for food or to protect territory. And then there were Paths like the Honorable Accord which was about acting honest and just and respectful to others, without any real caveats. Most Paths actually restricted violence in some way, even the extremely monstrous Path of the Night shuns killing without reason.
The Sabbat also had a complex political system, coming out of the original Anarch Revolt as neonate revolutionaries, but it now being centuries later when the original revolutionaries have become elders themselves and have become their own kind of tyrants, but with a lot of neonates still believing in that original spirit of the Sabbat. Political parties are a thing, with the Loyalists being essentially very similar to Anarchs except without the Masquerade, Moderates who want to pull back on the more tyrannical aspects of the Sect, and then the Orthodox and Ultra-Conservative parties that want to reform the Sect into a more explicitly religious cult/army ready to fight Gehenna. This is part of why the idea of the entire Sabbat running off to fight the Gehenna War in V5 was so dumb. The Ultra Conservatives would have been willing to abandon their domains to run off to the Middle East, the Orthodox would have probably sent people to fight but without abandoning their domains, and the Loyalists and Moderates wouldn't have given a shit.
