The Number 1 Defense Weapon Russia Is Vulnerable To

Russia since attacking Ukraine and under leadership of Putin have created the biggest war the world has seen since the second world war.

The main way they attack is shelling and the number one thing that works without doubt is HIMARS as pointed out by:

If more HIMARS are added and deployed in the weeks ahead it will make a significant difference.

And defense against all missiles from Russia that Ukraine need to end the war as Russia will not be able to keep this up under Putin.