Russian nuclear forces cannot outright destroy or overwhelmingly attrite US nuclear forces due to significantly higher US SSBN OpsTempo. Hence, Russian forces don't possess first strike capability. That's the freaking definition. I don't get how you can argue with this.
Russia relies on ICBMs because it is a land power and has a wealth of expertise in lang-based missiles. This has nothing to do with nuclear posture. And the ability to defend Moscow is hardly equal to first strike capability. Since US forces would still be able to massively retaliate against the rest of Russia, the second strike option is always maintained on both sides.