In a remarkable turn of events, the Times Newspaper of London published an article of 29 April in which it said Europe would struggle to put 25,000 troops on the ground in Ukraine.
If you can't deploy more than the 30,000 strong nazis that make up the two National Guard of Ukraine corps (Azov and Khartiia) then you can't be a peacekeeping force. These are the people you're policing and they've got more numbers and more experience in a peer war.
You're not going to be defending a deal from russia breaking it, russia is going to get what it wants. It's going to be the nazis wholesale breaking the deal because they aren't going to get what they want.