“Russia broke the agreement so what’s the point?”
Seriously? There needs to be another point?
You may be looking for the Minsk I and Minsk II agreements.
https://www.reuters.com/world/europe/what-are-minsk-agreements-ukraine-conflict-2022-02-21/
You may also looking for the Budapest Memorandum:
That’s the one where the Ukraine agreed to give up its nukes
for a guarantee of non-invasion, or some such.
Yeah, none of this says boo about NATO not allowing Eastern European countries into membership.