I don’t know about much weaker but likely a bit weaker depending on how allied campaigns end up going but we are very much talking relative here. A 9.3 million man battle hardened army in 1945 instead of 9.8 million man army is definitely weaker but not “weak” to the point that it is still them and the USA deciding what to do in post war Europe. To put in perspective the Soviet Army will even ITTL be about the same size as the immediate post war Greek population.I think the USSR will be much weaker position postwar TTL. The allies will likely defeat Bulgaria and Turkey, liberate Yugoslavia. Axis Turkey means less materials for the Soviets overall from the WAllies and more fronts for them.
I think most interesting would be seeing Greece ITTL be to the west what Yugoslavia was to the East OTL; someone who identifies with a “bloc” but chooses not to get completely subsumed in it. Greece will be hurting post war and may prefer armed neutrality vs the USSR rather than a NATO equivalent. Perhaps with a side deal that the USSR will not provide any arms to a Turkish state as the quid pro quo. With that the USSR gets a neutral state in control of the straits while Greece’s primary geopolitical adversary will be cut out of arms from the 2 main blocks and will rely on locally produced or whatever scraps are made by smaller powers.