Russia knows that if they want to keep annex countries, they'll have to take them piece by piece, with little resistance.
Your explanation and mine equally have zero credible evidence.
Given the fact that public awareness will quickly push companies to scan all software for vulnerabilities using AI, attackers will be making the most of this period to find daily flaws in hundreds of software packages that we previously saw as either "robust" or "robust enough" given the attack time/cost vs. incentive, before these defensive tools are deployed and operationally effective.
Nation state security services and rogue actors must surely all be scrambling to decide what to do with the millions/billions of dollars worth of exploit development time that forms their tool-set, including potentially using up zero day exploits etc.
The other factor is in the midst of such hysteria as "rouge agents" and other crap piped by the media, along with the actual risks of individuals with a few hours now having as much power as teams with weeks of time to spend did just a few years ago, coherent reports of what's actually going on is drowned in the noise. Attackers take full advantage of this.
Will it work, or will it harden their resolve to fight?