I don’t think this war was inevitable. There are no fundamental territorial or ethnic conflicts between Russia and Ukraine that are so significant that they would inevitably have led to war. This isn’t a fight over resources, either. That is why this war was avoidable and a negotiated solution was achievable.
Once the war kicks on then the calculus changes, positions harden and diplomatic solutions available before Feb 2022, are no longer on the table. I don't think a neutral Ukraine is a realistic option, simply because this would no longer be accepted by a large majority of the population in Ukraine.