I agree on the ending soon enough, however I think if Russia did hit a NATO state, Article 4 might not lead to an Article 5. NATO is already at a Article 4 so for the War so, so there is a huge amount of deliberation and intent to support without escalation.
Also even if Article 5 was invoked, it would be a question as to who would actual send troops vs "such action as [the member state] deems necessary" which is fairly broad.
I doubt article 5 would result immediately in boots on the ground, i can see strikes against naval targets in the black sea happening though or strikes against Russian defensive positions in Ukraine