Indeed, so - as already explained by others - Ukrainians are the Russian brothers and therefore it is comprehensible why the Russians did not attack infrastructure which is essential for the Ukranians like power plants or communication systems. In fact, they directly attacked the cities when the Ukrainians retreated within those (and therefore, at least partly, provoked civile casualties - especially when hiding in hospitals and schools) and one could argue that this guerilla tactic was the only defence option left for the Ukrainians. For Kiev it was to bind Ukrainian troops from defending the southeastern region. It was never about conquering Kiev.

For those who wonder why there seem so many vehicles lost by the Russians - they have a completely different tank strategy: the Western strategy relies on high-tech as-long-as-possible-operationable tanks while the Eastern strategy relies on the whole formation where a the single tank is not essential and losses (vehicles and soldiers) are part of the strategy of mass formation attacks with cheap equipment in order to be able to make huge breakthroughs with it (background: formidable battle formations against NATO). In contrast, they are not suitable for operations with guerrilla tactics.