Well, I think a deal similar to the one signed with Finland after the Continuation War might still be possible. Ukraine concedes even more territory, probably all the way to the Dnieper, Ukraine is made a neutral country, their armed forces are disarmed of all heavy weapons, and Russia places a permanent military force right next to Kiev and possibly other Ukrainian cities. But the Russian Duma is discussing going way beyond that.
If Ukraine was to remain as a country there would be Russian troops permanently stationed there and they would have to give up their heavy weapons. The only weapons they would be allowed to maintain would be small arms for policing duties.
So you think NATO didn't interfere in the war in Chechnya. You are quite naive. Chechnya's rebellion was being funded by the Gulf States, it had foreign fighters from Saudi Arabia and other countries fighting in it similar to what happened in Syria.
These people and weapons supplies were funneled in from NATO airbases in Turkey. I remember reading reports of the Russians tracking transport helicopters flying from Turkey to Chechnya all the time back in the Second Chechen War.
The only difference is that, much like in Syria, they had to maintain plausible deniability, so they used weapons fenced by the CIA instead of just giving them NATO weapons outright.
These Russian bombers are launching cruise missiles. They have done it before several times.
