I would say
"The Magicians" [my bold] got a little better from S01 to S02 to S03. S04 started out decent, then it sucked at the end of S04. And then the sucking continues into S05 because of S04 finale. And then they cancelled the show after S05.
I would have cancelled the show after what happened with S04 finale.
I thought S01 was boring as heck. I thought S02 was also mostly boring. But the reason I continued watching was because I got "invested" in the characters and wanted to see what happens to all the characters.
I was pissed at the end of S04 and that feeling is continuing with S05.