I can only speculate about who did this, but
It looks like there was a lot of disinformation being spread about Ukraine posing a threat to Russia. Russia is blamed for spreading the rumors, and these accusations appear to have been the justification for invading Ukraine. If it is true that Russia did this, than they did it to themselves (but that doesn’t answer the question of why they would do this to themselves). One thing is for certain, the information that President Putin was given about the conditions on the ground in Ukraine was complete fiction, so there is clearly a problem with faulty intelligence information.
Russia acted on information that was bad. Ukraine wasn’t a problem, but the rumors made it look like they were a problem. Coupled with the wrong information about conditions on the ground, you have the cause for Russia invading and getting bogged down.
You could be right If Russians were fighting in Congo. Half of Ukrainians speak Russian, millions of Russians have relatives over there. They were one country 30 years ago. There are still some soldiers on both sides, who served together in the red army and finally Putin is from KGB and Putin’s Russia is the KGB land - half of high rank officials have the KGB background.