I'd only point out that unless there is a Ruehin (already nerfed) on a row (any lock counters..), Slyzard (with Eredin) doesn't produce any points, he just prevents control cards from dealing points, so you can just do more points than the opponent does (Slyzard itself contributes only 4 power all this time, it doesn't change) to win a round, and keep Control for another round..
There are plenty of cards that can attack an immune enemy, such as various weathers and row effects (Lacerate, Traps)
If you don't use Scorch directly, you can use any card that creates a Scorch or Geralt: Igni
If Slyzard is freshly created using this amazing Wild Hunt mage whose name I can't remember, you can kick this mage to another row using Brouver's charge and kill 4hp Slyzard using a 4-provision pts Elf who's got 1hp and auto attack for 4dmg