It was actually good when it is treated as a stand alone movie with great songs and references to the og series.
Making Clawdeen as the main character rather than Frankie like the og series it gave the creative team more opportunities to explore, build on and reinvent her story which the og series is kind of lacking. By making Clawdeen half human half monster, it explores the feeling of not fitting in to a particular "group" or "click", trying hard to change it and finding where you belong (a reference to teenagers nowadays). Finally, although it it just my option, I love the costumes and the location. It is both stylish, natural and gothic at the same time.
However, aside form the characters, the school and the personality of some of the character , there is no other connection to the og series to be considered cannon or "a multiverse". Adding the witchcraft element is a bit random since it did little to make the plot go forward, aside form adding a little something to Draculaura character and can clearly replaced by something else, and it it didn't even tried to clearly explained it in the movie.