Do it fast, then, and now, while Putin is massively tied up and likely to be for a decade pacifying a well-funded and equipped insurgency.
https://yle.fi/news/3-12272467
> "If Finland and Sweden applied for membership, we could decide on it overnight. You could be a member the very next day because you meet all the necessary membership criteria," said Rasmussen, who was Nato Secretary General from 2009 to 2014.