No, it wouldn’t. You can have a World War without global superpowers on both sides (you need a wide geographic alignment of such power to, balanced for the relative difficulty of force projection on both sides, reach aggregate near-parity across a widely geographically dispersed set of conflict theaters, but you can do that with a global superpower on one side and a coalition of major regional powers in different regions on the other.
Should it expand beyond a major European war: Iran, Syria, North Korea, China are among the more obvious potential out-of-region Russian coalition partners; there's also quite a number of situations in Africa that could also be plausible areas of expansion of the same geopolitical conflict.
No, it wouldn’t. You can have a World War without global superpowers on both sides (you need a wide geographic alignment of such power to, balanced for the relative difficulty of force projection on both sides, reach aggregate near-parity across a widely geographically dispersed set of conflict theaters, but you can do that with a global superpower on one side and a coalition of major regional powers in different regions on the other.