Locke and Key is a bumpy road of merging directions and fails to ever have a moderately consistent tone. Some great episodes mixed in with utter rubbish; lots of filler episodes that read like a cringe-fest teen drama. (aka a typical netflix series).

Is it a spooky horror show, is it a melodramatic glee reject, is it a suspenseful thriller, is it a boring soap opera complete ominous overly dramatic piano tones?

Yes and yes and more yes, pending which season/episode you watch.

By season 3 they verve off road after episode 1; first some side character marriage becomes center (no background or any meaning to story, the extra character and marriage just "magically" appears). Just political messaging, fast forward. Character disappears just as quickly (thank-you for wasting my time).

Next couple episodes are bunch of drama and whining; the 5-10 mins the main protagonist gets is the only good parts.

About midway through season they start to get back on track to actual story as the protagonist picks up the pieces and re-introduces thriller/horror concepts.

If you don't mind wearing out your fast forward button; worth watching.