Relationship between Russia and the west will probably be restored at some point but not without a lot of Russians and to a lesser extent Ukrainian getting killed, their economy and infrastructure gutted.
If you look at Iran, it also has its infrastructure in quite OK conditions - perhaps in better shape than all of their neighbours, and now that may even include Turkey. Russia is larger and has not self-inflicted being a theocracy.
As for the losses of both sides, I'd suggest leaving that to military experts.
https://www.forbes.com/sites/davidhambling/2024/01/25/ukrain...
In either case, even a Ukrainian defeat means Russia will be a pariah state to countries with reasonable governance. Trade will be difficult and diminished, same as it is with Iran.
Putin&Lavrov have clearly made this calculation and decided this is in their own interests. Whether it's in the interest of the Russian people I think is questionable.
If anyone's wondering why Iran has its fingers into Syria and Iraq militias, note they've been invaded (with US support) by one, and are allied with the other.
It's sort of a moving target like "How long would it take for Freddy Krueger to kill all Chinese teenagers"