Vietnam had jungles that gave them an advantage, in Afghan they had mountainous regions that were hard to control and they kicked back in Pakistan till America left, Chechnya also has mountainous regions that helped the defenders
Once again what advantage does Kyiv have to balance the odds? Since this conversation was about arming the population of Kyiv to fight back.
You didn't even believe insurgencies are possible outside of star wars a few posts back... now you're making up requirements that a successful insurgency must have mountains etc.. Ukraine does actually have some mountains btw... and forests.
The important thing though is the support of the civilian population. Where were the mountains and jungles when ISIS swept through parts of Iraq and Syria?