If Russia does invade, it will change the world.
The big news is that it is happening this week.
It would change Ukraine but the rest of the world may vary. It won't change Asia, Africa or South America. It won't meaningfully affect the American public who cheerfully ignored A-stan for twenty years. It's only a war and if you're not in combat that's a spectator sport. Noobs don't seem to get how common kerbstomping small states used to be. It was the norm because it worked.
It will be news like Hungary or Czechoslovakia. No one not Hungarian or Czech or a political or military enthusiast gives a shit about those today. Once the situation stabilizes this thread will drop back out of sight.
It will change on a diplomatic level at least, and i think in ways where the world will rearm itself as no deals will be worth anything anymore, while Russia will probably have a stronger appetite for something more along those lines, but it depends on how that first step will go first and what happens during before i will make a bet.