What diplomacy would you suggest, given the other goal of "Russia cannot gain anything from the war in Ukraine"? Russia has made blantently clear with their war in Ukraine that they want the good old USSR back, and I (and most of the population of Eastern Europe) have little faith they'd stop there. That's the reason Ukraine is getting so much support: if Russia gets even a little bit more land from this war, they'll just try again. They got Crimea basically for free and they took that as a signal they could keep going. Why would they stop taking land if no-one bothers to stop them?
And, yeah, duh. I would suggest, if they want people, that they treat their population with some respect so that fertility rates aren't in the ground, they don't have a massive brain drain as everyone tries to leave, maybe some people might want to immigrate, and oh yeah, maybe don't have a war which absolutely decimates their population of young men? Russia could be so much better if they sorted their own shit out before making it everyone else's problem, but that would involve Putin loosening his grip on power.
And, yeah, duh. I would suggest, if they want people, that they treat their population with some respect so that fertility rates aren't in the ground, they don't have a massive brain drain as everyone tries to leave, maybe some people might want to immigrate, and oh yeah, maybe don't have a war which absolutely decimates their population of young men? Russia could be so much better if they sorted their own shit out before making it everyone else's problem, but that would involve Putin loosening his grip on power.