There are no stakes! Why, why would they make the heroine the most annoying, unlikeable character ever?
Season 1 was somewhat enjoyable, Season 2 less so, but wow, season 3... watching it felt like eating a very large, very cheap piece of steak. You don't like it, but you keep eating it in the hopes it'll get better. And you've already started, so may as well push forward. When it's over you regret everything.
First off, the sets look like they cost $20, and that wouldn't have even mattered had the writing not been so, SO bad. The low budget sets were the least problematic issue (even though they go to freaking Hell of all places... come on? You referenced Bosch, where is the inspiration??)
Ah yes, the writing was truly terrible. Among many atrocious moments, there was a scene at the end where the writers were literally like, "Oh, there needs to be a conflict here to drive the plot forward. So let's have Sabrina do the most stupid, nonsensical thing she could possibly do. There, now she's in trouble. Problem solved!" You can't just do that. It's just the laziest form of writing possible.
Second, there was WAY too much exposition. I guess that can't be helped if you're basically inventing all the rules to a crazy made-up universe... but again, lazy writing. You can make anything work if there's believability. Take Harry Potter for instance - the world and the witchcraft is totally believable, even when there are CGI kids for crying out loud. Here it's all tell and no show, nonexistent and inconsistent rules.
All this was made worse due to the poor acting all around. When Aunt Hilda is the best character in the entire season, there's a problem. Oh, and what's up with the random musical numbers? Please stop. It's not cute, it's cringe.
Just because it's a show about witches, it needs to feel like there are stakes. Here there are none, even when the stakes were a matter life and death. I think I'll pass on season 4.