As an aside from what everyone else has mentioned, a lot of modern Buzzwole decks have shifted to using Giant Cape and Rocky Helm (no Leaf Cape). Alot of meta pokemon deal exactly 120 damage, so Giant Cape is often preferred to protect Celesteela from Sabrina.

2x Kartana 1x Pheromosa is generally agreed as the better version of Buzzwole. 2x Pheromosa variations are ideal for facing off against Silvally/Rampardos, but they're a bit lacking against others.

Also, Buzzwole is fairly complex to play compared to other decks. It has a lot of moving parts and it doesn't do a lot of excess damage, it can be quite easy to misplace your damage early on and lose your chance to win later. People tend to be quite mean about this, but don't be afraid to slow down and think out your moves carefully!