When Russia attacks Ukraine, it would be the perfect time for China to attack Taiwan. It is essentially a middle-out tactic where the defense forces are split.

Russia needs Ukraine. China needs Taiwan. Both locations are perfect "control areas of the battlespace". Any military commander would recommend an attack.

The real issue would be direct force-on-force confrontations between Russia/US and/or China/US. So far the superpowers have avoided this and worked through proxy fights. Even in Syria the US was VERY careful to avoid Russian troops.

However, in Taiwan, there are US service personnel. I don't know but I suspect there are also US "advisors" in the Ukraine. Direct superpower attacks won't end well.

The situation will get wildly out of control VERY quickly.