Russia is planning to exhaust Ukraine

Afraid of inflaming Russian anti-war dissenters, and reluctant to send more troops, Russia has been accused of launching waves of so-called "kamikaze" drones against Ukrainian cities and power stations in recent months. Ukraine's government and Western intelligence agencies say Russia has been using Iranian-made Shahed-136 drones in the conflict since autumn last year. Also called the Geranium-2 by Russia, it has explosives in a warhead on its nose and is designed to loiter over a target until it is instructed to attack.

https://www.bbc.com/news/world-62225830