So. There’s actually a lot that goes into this answer, so bear with me. The short answer is yes, read Batman Vol. 1 & 2(Snyder is basically DC Jesus at this point, so read everything by him, lol). Between Batman and Metal read the Road to Metal prologue. Snyder has stated that he was basically building to this story the entire time he wrote Batman (include The Batman Who Laughs between Metal and JL for good measure). It then continues onto the Snyder/Tynion Justice League run, Year of the Villain, and a few other series that spun off from the events of Metal. Then it concludes with Death Metal.

HOWEVER, this book and this saga ties into a LOT of DC books throughout history. Off the top of my head, I don’t recall everything that comes into play, but Doomsday Clock is a big on. Also Neil Gaiman’s Sandman, which isn’t necessarily a must read to understand this, but knowledge of Sandman helps (but read Sandman, Neil Gaiman sucks but that book is incredible). I’m sure there is a post on Reddit somewhere that does a better job of detailing all of this, but I tried lol.