Raven is the only practicioner we have so far she would have much trouble defeating, and Black Adam is the only Practicioner we've met who would be likely to defeat her.
While I won't make a statement one way or another about your overall point in the post above, this statement is blatantly false. While Raven is the only practitioner who is a LexCorp employee who Cassandra would consistently have trouble defeating, in situations in which Cassandra does not have access to a gun or some other form of ranged weaponry and the fight is in an open area, Cassandra would also struggle against Rebecca using her powers optimally (Rebecca can fly and remain out of Cassandra's range while blasting at her with hellfire). If we look outside of LexCorp the toss up on characters that practice magic that can give her a lot of trouble includes people like Zatanna (if Zatanna has time to start casting, she can be incredibly difficult for Cassandra to beat considering Zatanna can very quickly begin immobilizing Cassandra and pull off devastating tricks like magically making Cassandra unable to see).
As for practitioners that would be likely to defeat Cassandra that you've already met, I can already think of at least five who are likely to do so (and one additional individual who probably has the odds in his favor with a huge asterisk attached).
- Doctor Fate folds Cassandra so fast it's not even funny. The biggest advantage Cassandra has in any fight with Dr. Fate is that Dr. Fate can't go to full power without allowing a Lord of Chaos to potentially drop in and successfully gank him.
- Circe is a goddess full stop. While Cass can hurt her avatar, Circe is able to near instantly end a fight by transforming Cass, can fly, can fire blasts from long range, can create minions to fight for her, can shapeshift and is immortal and very, very durable. Unless you are incredibly magically powerful/have powerful magical defenses, any direct fight with Circe is an instant loss. To be fair this is not a knock on Cassandra's capabilities (she has about as much chance at winning a straight fight against Circe right now as Superman, the Flash and Batman teaming up together do), rather more me pointing out that Circe is a goddess and is pretty insanely hard to fight (you need Moly to even have a ghost of a chance 99% of the time).
- Karkull also bodies Cassandra. Karkull was basically able to turn Metropolis into a hellscape in under an hour. He's one of the strongest mortal practitioners ever. He can transfigure people, teleport, fly and turn invisible and intangible. Cassandra cannot even touch Karkull even if he dropped half his abilities like transfiguring her into his minion, turning invisible and teleporting. Karkull successfully managed to fight Ultraviolet, Superman, Silver Banshee and Dr. Fate all at once and while he did have minions, it didn't exactly take him a long time to build up that many minions. He easily comes out on top.
- Tala might not seem impressive as you've seen exactly zero impressive feats from her, but she's a very, very powerful magic user. Beyond the classic flight advantage, Tala's several centuries old and is incredibly magically powerful. Cass could maybe beat her if the fight starts with Cassandra right on top of her, but in any situation in which Tala is able to cast a single spell, Cassandra probably loses.
- Mera is another character who I don't see Cassandra beating. While Mera isn't the most impressive magically, the ability to control water, breath indefinitely in water and the general Atlantean super strength and durability package are not great for Cassandra. Cassandra could get the upper hand in a drawn out engagement, but in any situation where Cassandra is forced to fight without retreating, she probably loses.
- Felix Faust is the character with the asterisk attached. Felix Faust is absolutely incredibly powerful but you're unlikely to encounter a full power Felix Faust and any overt unleashing of his power that allows various even more powerful entities to locate him would result in him/that part of him also dying. Felix Faust could pretty solidly trade against Cassandra if he were willing to die and if Cassandra were ever made to fight against a whole Felix Faust as opposed to a sliver of his soul possessing someone else (which is what you encountered) then she loses pretty solidly.
So that's six magic users who you've met who more likely than not defeat Cassandra who are not Black Adam. To be fair, two of these characters are what I would consider the best in a particular field of magic (Faust and Karkull), two of these characters are multiversal entities (Circe and Dr. Fate), and the remaining two are a centuries old witch with training from one of the most powerful magic users in the world when he was significantly more capable and the other is a super tough, superstrong princess from a warrior culture who became the queen of Atlantis and studied magic her entire life.
I just wanted to point this out because you've already encountered plenty of big magical fish and I think that's worth bringing to your attention since I personally wouldn't even place Black Adam in the top 3 most powerful magical beings you've encountered thus far.
@King crimson if the update is being released in chunks, is there a new timetable for it?
Not really. I might get it out early but realistically speaking I have this evening and portions of tomorrow before IRL obligations tie up too much of my time to realistically work on this (I've gotten an interview every day of the week at this point and clinic work and coursework that I need to keep up with and birthdays to attend and I don't think I can realistically get all of this done and work on the update efficiently).
Expect the time table to hold about the same though things might get lucky (though I wouldn't bank on it).