Galarian Slowking is superior to Galarian Slowbro thanks to a couple of important factors:
1.Chilly Reception:
Slow pivoting is an invaluable resource for bulky offense and balance teams, allowing frail teammates such as Darkrai to get in for free. Chilly Reception combined with Future Sight pressure allows teams to overwhelm balance and stall structures, as Dondozo is forced to take a Future Sight while it is trying to wall something such as Kingambit or Zamazenta. Chilly Reception also has great synergy with Choice Specs Kyurem, giving Kyurem a free switch and a defensive boost.
2.Great SpDef bulk:
Combined with an Assault Vest, Galarian Slowking is a useful glue that can check a myriad of Special threats such as Choice Specs Kyurem, Primarina, Enamorus, and Raging Bolt. Heavy-Duty Boots sets can also do, keeping hazards out of the equation at the cost of some bulk. This with Chilly Reception and Regenerator allows Galarian Slowking to check these threats very consistently.
Galarian Slowbro can do neither of these essential things, giving Galarian Slowking viability while Galarian Slowbro is not viable.
Hope this helped.
