The intelligence services were engaged before the invasion. Somebody in there gave the US Putin's playbook. Biden was publicly calling out Putin's moved before he did them because of this.
Somebody in the FSB has also been feeding intelligence to Ukraine. I personally think the FSB letters are real, but regardless of whether they are or not, some details are congruent with the intelligence passed on to the Ukrainians and US.
This shows that there was enough concern within the services about the leadership failure that they decided to tell the enemy Putin's plans. The FSB letters describe the process, this analyst is told to write a rosy report, and then their boss rewrites it to be more rosy, and as it goes up the chain it's further warped to sound rosier until it doesn't look anything like the original report which was fiction to begin with.
The FSB letters doesn't say whether or not this is new, but I suspect the intense spinning of facts is fairly new because Putin is less tolerant of bad news than he used to be.
The Russians have a lot of problems with their military, corruption, one horse economy, etc., but their intelligence services developed during the cold war were in the same league with the best in the world, and all evidence is they have stayed close to that level since.
The US can win a conventional war almost anywhere, but that's not winning the whole war. If the US had approached Iraq like they did Japan and Germany after WW II they probably could have won the peace, but once an insurgency gets going, all that weaponry is of limited usefulness. In the end the US left Iraq with its tail between its legs because it couldn't win the insurgency. The US won the first phase of the war easily, it lost the war.
Insurgencies are hard to win. High tech weapons can help, but boots on the ground is the most important thing. The magic ratio is 20 troops per 1000 population. Less than that, an occupation is almost certain to fail unless the civilian population is accepting the occupation. In the last 120 years, less than the magic ratio worked once in Japan after WW II.
Putin wants to cast this war as a war with NATO because the Russian public can get behind a war with NATO. 40% of the Russian public has relatives in Ukraine and don't have a big beef with Ukraine. That has led to less than wholehearted support for the war in Ukraine.
Interestingly I was talking last night with someone who recently had a Zoom call with fellow professionals in Ukraine and Russia. The Russian was initially in favor of the war until the Ukrainian made him aware of just what was happening in Ukraine. When he realized what Russia was doing there he was horrified.
On another note, I have been saying from the beginning that Russia can't win this war. Another thought ocuerred to me today. If Russia were to defeat the Ukrainian army and occupy the country, they won't be able to put a puppet in charge because the puppet would have a shelf life measured in minutes as soon as Russia leaves. The Ukrainians would immediately switch to an insurgency and they don't have enough troops to win.
On top of that, the rest of the world would likely just keep most or all the sanctions in place until Russia withdraws and most likely until Russia agrees to restore the 2013 borders for Ukraine. Russia can't take the financial bleed for very long.
The only question as this point is how badly Russia is going to lose.
Unfortunately Ukraine is going to continue to get trashed until Russia runs out of resources.