Just logistically speaking, imagine needing to send dozens of different types of dozens of spare parts to different sections of a thousand-mile wide front line, with different types, shapes and calibers of ammunition as well. These tanks will likely just be abandoned after they get even slightly damaged.
It is also unclear to me who is supposed to be in these tanks. If Ukrainians are going to operate them, even if they are already familiar with Western-type tanks, the entire reason Ukraine needs new tanks is that its old ones got destroyed, which presumably means there aren’t that many people left who can even do this. If it is going to be Westerners, they would be unused to waging battle where instead of them, it is the enemy who enjoys artillery support, air supremacy, satellite reconnaissance, numerical superiority, and technological advantage; and they would also be entirely unfamiliar to the geographical difficulties Donbass tends to exhibit with the changing seasons.
I don’t think NATO is trying to win the war. It just wants to drag it out. NATO needs to be at war all the time. It can never stop being at war.