Enjoy the first film and avoid the second if you can.
Spoilers below
They could have explained the return characters by stating that the original cult was immortal as they had performed the ritual before and asked for eternal life, adding the before sunrise to complete the ritual part was unnecessary.
They should not have made Melanie evil in the sequel, that was a dumb choice.
They should have just rocked up and found the cult still active but in a different location as they were forced to relocate following the events of the first film.
Jenny Ortega was not required for this sequel.
It's was frustrating to see all of the effective story beats from the first film undone.
Seeing the return characters was a joy but the execution was all wrong unfortunately.
I'd have been much more satisfied if they were undone by burning the book, having the wrong blood ingredients should have just made it ineffective. It shouldn't have even affected evil Melanie as she was not a demon. Ugghhh frustrated.