If you think Russia can never be trusted you'd have to say the same about the other countries failing their security obligations. Those who guaranteed Ukraines territorial integrity, the US, the UK, didn't act and send their own troops to stop the invasion.

IMO the friendly way hasn't been tried as NATO also didn't care about how Russia feels about this and that. The story is well known. There's not a single country or single person to blame but many of the involved actors.

To me it's lunacy to think Russia will be defeated and split up. Who's going to defeat them? With which soldiers? Europe is an old continent, there are so few young people... It would be the final demise of the European economy having to fight a war with Russia. And do you consider the risks? Russia has nukes. Before anything even remotely to the scenario of being split up happens, it will have used them. No sane person can ignore this threat.