Zama is fine in my opinion because it does like absolutely nothing into fat teams. Even sub zama really struggles into Sinistcha, Gholdengo, Scor, Mola, Corv, Molt, Zap, etc. Offense also has numerous ways to beat it, such as running Pult to force it out and burn Dauntless while keeping up pressure, running Iron Moth to again force it out once while keeping up pressure, Iron Valiant doing similar things, Landorus-T forcing it out and pissing it off, Tera Flying Roaring Moon, spinblocker Gholdengo, etc. A lot of offensive or HO-leaning Pokémon, while being unable to counter it, check it enough for it to burn Dauntless and become unable to consistently sweep or check the team's numerous offensive threats. While yes, Zamazenta is IMO a top 2 Pokémon at least, and one of the central forces in the metagame, I consider it downright healthy as a way to punish offense and check the numerous Darks in the tier such as Kingambit and Darkrai. I feel like those clamoring for its ban are too focused on what it can do in theory instead of what it actually does in practice.