It's obvious to anybody who has even the bare minimum of understanding of what's happening in Ukraine. Don't take my word for it though. Here's what Lt. Col. Alex Vershinin retired after twenty years of service, including eight years as an armor officer with four combat tours in Iraq and Afghanistan and twelve years as a modeling and simulations officer in NATO and U.S. Army, working on concept development and experimentation has to say on the subject:

• https://www.rusi.org/explore-our-research/publications/commentary/attritional-art-war-lessons-russian-war-ukraine
• https://responsiblestatecraft.org/coalition-of-the-willing-ukraine/