Miltank

Miltank differentiates itself from other Stealth Rock setters thanks to its access to reliable recovery in Milk Drink and resistances to Fire- and Ice-type moves with Thick Fat. Unfortunately, Miltank is extremely passive, as it relies on Toxic and Seismic Toss to deal any sort of meaningful damage. It also still ultimately loses to Pokemon it's supposed to beat such as Incineroar, Delphox, offensive Rotom, and Magmortar despite its resistances and immunities. Miltank also struggles to do anything to Xatu or teams with it. Despite lacking recovery, other Stealth Rock setters such as Steelix, Rhydon, and Druddigon arguably all offer more defensive utility and are much less passive than Miltank; Rhydon has Swords Dance, Steelix has Curse, and Druddigon has raw power.