I've got shelves of Reminaginings for fairy tales so going into this series I was open to just about anything.
It's not an exact match but the title is the best way I can describe how this show felt to me. It's like each fairy tale story was prompted to be mixed with a Sci-fi anthology series and the sound track was sourced from classical composers, though not always in a classical style.
And yeah the tones here all over the place while also being similar. It's really best to view each episode as it's own because really the only thing tying them together is the short openings with the Grimm siblings discussing the original fairy tales, and eventually having some small cameo in the story of the episode. So very " Rod Serling" or Alfred Hitchcock.
As others have said with no spoilers
Cinderella is closest to the source material with a 'dark twist' so I'd say it best matches Night Gallery
I found a special fondness for Red Riding Hood which had shades of Hannibal and Black Mirror
Hansel and Gretel feels more Twilight Zone still a little twisty but nowhere near as dark as either of the previous tales.
Elves and the Shoemaker totally lost me I'll be honest, I won't even pretend to understand what happened there but then even the Main Character didn't even get it so maybe that was the point XD.
The Town Musicians of Bremen would be right at home as an entry for Love Death & Robots.
The Pied Piper Of Hamlin is rather Tales of the Darkside or maybe one of the more mild Master of Horror episodes.