Putin is not prolonging the war. His army, while large, just sucks.
The Russian failures include: underestimating the will of the Ukrainian people to fight back as he thought they’d just welcome his army as a liberator; attacking on too many fronts and spreading his forces thin including not planning for resupply and reinforcements which is ultimately just poor planning and tactics (only 1/3 to 2/5 of his estimated 190,000 force are combat troops, the rest being, supply, transportation/truck drivers/pilots, maintenance and ground crews, radar and communications, hospital staff, cooks, etc.); poor leadership and training as the Russian soldiers can’t do a thing without orders from the top; poor morale of a conscription force that didn’t even know they were going into a real war (videos of capture soldiers show this); poorly maintained equipment (trucks with flat tires from cheap Chinese rubber tires) which is likely the result of the Generals stealing funds instead of spending it on equipment; and so on. The only strategy left to them is siege warfare and terror tactics by bombing the cites from a distance and targeting civilians until they surrender. But the Ukrainian resolve is going to eventually beat them back.
Putin wanted to destroy NATO and a 2nd term of Trump might have had the US pulling out of NATO. NATO is now more unified than ever. NATO countries will ramp up defence spending to meet their 2% GDP target (Germany is fast-tracking that now). Canada needs to do the same and should get newer and more submarines, should serious consider an amphibious assault ship or Landing Platform Dock (LPD), Apache attack helicopters, many more tanks (we have less than 70), more drones ranging from the attack drones with air to ground missiles and smaller drones for small units to target enemy positions for artillery and mortar missions, more man portable anti-air and anti-tank (stingers, javelins, Carl Gustovs, MLAWs) etc. We might see Finland, and maybe even Sweden, who have been neutral make a bid to Join NATO if they see Russia as an increased threat to their safety and security.